I think we should pay respect for the engineers of the day that made this thing possible, it is brilliant engineering at it's best. VCR's should not be taken as granted because a lot of thinking and designing went into them starting from the VTR's of the 50'.
@@hugh007 which also helped doom the industry, as servicing the units became economically unfeasible. Then, digital storage entered into the picture and put the final nail into its coffin. Beyond hardware failures, like belts failing, just cleaning video heads, one would look at the cost of paying a tech vs sandpapering, erm, I mean a "cleaning tape" to abrade the heads clean and call it done and wonder what happened to the video quality. It was literally like cleaning your car by using sandpaper. A belt failed, landfill it and replace the machine. Gave up the field around '98 when everything in consumer electronics became completely disposable and went into IT. While the computers may be reaching a similar state, networking and data transfer remain economically viable. I'd started repairing consumer electronics for a living in 1980, learning VCR's, then CD's, DVD's, etc as they came along. Repaired to component level everything from vacuum tube circuits, hybrid vacuum tube and bipolar transistor based circuits, later incorporating integrated circuits, VLSI when it ambled along, comb filter IF's until the industry essentially collapsed and IT was growing. Now, well I just looked up to see if VCR's are even still being sold and I was a touch surprised to find that they are. I've been storing video on hard drives, with backups and important videos go onto a RAID array. Drive fails, there's a spare to automagically switch in and rebuild the array while a replacement gets installed. More amazing is to see the machines that wound those heads. Tiny ferrite chip heads, wound with tiny wires thinner than a human hair, manufactured in bulk. That in and of itself is a major accomplishment in technological handling of components! Manufacturing to submicroscopic tolerances, another major accomplishment.
Thank you for this demonstration. I find it amazing that such precision and tiny engineering was possible these days at a price that was relatively affordable. In addition they have made this serviceable, which is a lot more than you can say about modern electronics today where the service guy is treated like the enemy of these modern manufacturers
I came across a magazine called Video Repair or something. I think it was a late 1980s or maybe early 1990s issue where there was an article basically saying that VCRs and other video equipment had become so cheap that the economics of repair would not work anymore. The article suggested switching to quick diagnostics of which sub-assembly is at fault, and replacing complete sub-assemblies instead of repairing each tiny thing like a head on a drum. I guess this worked when parts were cheaper than a complete unit. Nowadays I can buy a new phone for less money it costs to replace the glass on the screen. But I am keeping my 2013 MBP, had battery changed recently. Damn Apple glues more things together from generation to generation, making it less repairable despite the whole "Right to Repair" hoopla. Tesla does not even allow anyone but Tesla techs to work on their cars.
@@12voltvidsi have a 8mm video tape that has specs in and outside of the reels, when i fast forwarded the tape, some dissapeared, but theres still stuff on the inner reel that did not stick or stay on the tape. Is that mold or some sort of plastic mark?
There's an important concept you need to understand, it's called "economy of scale". It probably was expensive to design and manufactuer the first couple units, but once they had a market scaling up production made a huge difference. Individual units cost a lot less when you're making tens of thousands of them and the expenses of dedicated machinery are swallowed up by the revenue stream.
@@12voltvids You need human beings to provide support and servicing, people are expensive. And you can't turn off human employees when you aren't using them/benefiting from the work they do.
What’s really amazing is the timing of everything and how the tape is moved against the head. The fact that the head moves in a helical fashion across the tape (head is angled and spins diagonally across the tape). That is some clever control and servo systems for sure.
@@12voltvids not quite on its own. The control track itself is quite broad and low frequency. Servo tolerances were tight out of necessity, as were mechanical tolerances. At the time videotape was introduced, such tolerances were literally unheard of in consumer goods of any sort. In a very real way, they were practice for the development of yet to come optical media, with its even tighter tolerances. And the components themselves in just the mechanical, think about it, one's recording on what's literally an abrasive, yet somehow the guide rollers and drum proper didn't get abraded out of tolerance or as bad, polished until stiction became a tape fixating problem. The heads actually penetrating the oxide layer slightly and not swiftly wearing out. That's a *lot* of metallurgy and mechanical tolerance knowledge being applied - then the servos can come into play. Yeah, used to repair these, initially picking them up on my own as televisions started to move toward becoming disposable. Became proficient in VCR's and as their prices plummeted, moved into CD and DVD service... Industry grows, one grows or stagnates into poverty, I just grew and learned how the device operated to its lowest levels, which gave me an edge on peers that couldn't comprehend those devices fully. Always did get a chuckle over those who just refused to learn. They'd never figure out a problem in a PLL or even an SMPS and I'd get to eat their lunch. Tried to show some, but if they really didn't have an interest, they'd never learn.
I often inspect heads under a microscope like this. Surprisingly perhaps, it's not easy to spot head wear, completely worn out heads usually look fine. But damaged heads can sometimes be seen. V2000 format heads are interesting as they sit on piezo electric actuators (as do some Betacam and MII ones I believe).
@@video99couk And all of the 8mm formats, probably miniDV and even DAT uses piezoelectric tracking. Sony licenced the technology from Philips' V2000 format when they were developing the Video8 system.
This one reminds me of my first Beta VCR that I bought when I was around 12 years old. It came with a box of tapes. I was so excited! The picture quality wasn't great though and the internet didn't exist, so I tried to clean the heads myself without much clue, and the result must have been what you showed here with the broken head. Nothing but snow was my reward after that 'cleaning'. An early life lesson though!
Just wait for the next one where I will attempt to transplant a drum from an old UMatic playback only machine to that VO5850 that had the open coil. Wish me luck. I'll edit that as soon as my computer is available, which it isn't now because I went to the airshow yesterday and took some pictures of old airplanes doing tricks. 4K video takes forever for my old PC to deal with. 12+ hours to render out less than a 60 minute program. File size will be about 100 gigs LOL
And a beta head the tape was wrapped almost all the way around, versus a VHS only half. I worked on them for years in the 80’s…thanks for the trip down memory lane 🙏👍
The tape was in contact for the same 180'. Just beta pulled more tape out using a U loading system just like the professional systems. This resulted is less bending of the tape, resulting in lower tape tension which allowed the tape to stay threaded. Until the mid 90s all vhs unloaded the tape to ff and rewind. This was due to the design. They had to make several changes to allow vhs to remain loaded and this added more points of failure like the pinch roller that lowers down on the back side of the tape. Beta was better in every way except marketing and that Sony wanted it to be profitable whereas jvc just wanted to give it away. I think if one were to look at profit margin on each beta /betacam unit sold Sony came out on top. Their professional betacam format very quickly became the field production source for production. If you saw it on TV shot between 1982 and 2015 there js a very good chance it was shot and edited on betacam, betacam sp, betacam sx, digibeta or hdbeta. It was pretty much the only format used. That professional format grew from home betamax and betamax evolved from 3/4 umatic.
It's a miracle these things work at all. Looks like some garage project. Amazing you can get a high quality video signal from something that looks so ungainly and crude looking.
I remember the first family vcr. Not a clue about them, I looked inside through the tape slot and thought why is the big motor on such an angle 😂. Since then I had a fascination how vcrs work and am still amazed by the way they recorded and played back tape.
Well I actually looked at a VHS drum I'm having floating around after watching this video, through a vintage optical kit microscope, that has about the same magnification, or maybe a bit more. I looked at a stereo cassette tape head too first. I could notice what a schematic I found on the internet calls 'index error', that's a tiny 'shift' between the two poles of each heads perpendicular to the tape direction, as well as on the shielding plate between the two heads, but not unexpectedly, I could not see the gap itself, even at that magnification. And then I looked at the video heads, making sure that some light shines off them, so I can see the edge of them that's facing the tape, properly. I could clearly see a narrowing in the middle of both of them, I assume those narrowings define the effective width of the tracks that these heads record and play. At no moment I could be fooled that what I see is the gap itself, if those were, they would be far too wide. Needless to say I just couldn't make out the actual gap on those, again, not unexpectedly. Those are *extremely* narrow gaps, that normally the magnetic field would have *no problem* whatsoever jumping through, but there's a very thin gold spacer in those gaps. Gold is diamagnetic, it pushes magnetic field out of itself. So far I found no data on the size of the gap, but it must be anywhere between just a few micrometers down to a few nanometers. That's really just my broad guestimation. Right now I can't find any source on the gold layer or foil, but maybe you heard of it. I just don't remember where I read about that.
The narrow part is the track width, the actual gap is much smaller than that typically only a few microns. Would need a much higher power microscope than this to see the actual gap.
I always thought the secret sauce was actually the metal disc with the concentric circles. I never knew there was tiny coils mounted to the edge. Thanks for the lesson.
Back in the early 90s I replaced the heads on a few VHS machines. Not the whole drum though. I was swapping out heads from different machines that were broken and a couple times I was able to purchase heads I needed from a local repair shop. Somewhere I had found documents that showed most makes/models and which ones used the same heads, and with their part #s. That helped out a lot being pre internet. My old eyes would need that microscope today though. Lol And thanks for showing the Beta head! I'd never seen one of them up close. Interesting in how the two types compare.
@@12voltvids it is doable, though time consuming and tedious! That is probably why the whole drum was replaced. Plus replacing the whole upper drum made repair shops more money.
I can't see the width difference of the head chips, probably because this is a time lapse head drum. Time lapse VCRs use two sets of the same width head chips (probably EP width), one set for recording, one set for real time monitoring off tape. This is necessary to prevent creating a week worth of failed CCTV recording when a head clogs. Also this looks like quite a garbage quality aftermarket head. The head chips seem chipped at the gap, there's hardly any material left on one of them. Thanks, this is an interesting video, I'm continuing now from the 6:40 mark where I paused to write this comment. There is/was a Czech guy on YT who hand wound video head chips under a microscope. He done that for big 1...2 inch studio VTRs, IIRC he removed head chips from VHS drums by dissolving the epoxy, glued the chip on the VTR's head and wound it with a set of super fine tip tweezers. It was incredible. I subscribed on his channel about a decade ago, now I can't find him, maybe they removed the channel because he showed TV footages that might have caused him multiple copyright strikes. I'm sorry I haven't downloaded at least some of his videos. I was glued to the screen, despite I couldn't understand a single word.
Only if I commented a few seconds forward into the video... So it isn't the whole chip that is of video track width, they are only narrowed down at the gap. Makes sense, if the whole chip would be 22um width, it would be very fragile, probably impossible to mass produce.
It wasn't a time lapse. It was a real time that could operate in 2H or 24h. Basically there was an alarm input. Close the contact and it kicks to 2h. The head was a standard 4 head for mitsubishi vcr. The quality of the 24H speed wasn't bad and you could play the tape back on the machine but if played on a regular machine it played 4x normal speed. It used 19 micron heads and you can see the difference on camera. You might be looking at the wrong place.
@@12voltvids Yep, I expected the whole EP head chip to be much narrower, but instead it is only really narrower around the gap. Did your CCTV VCR had real time monitoring? It is a must IMO, because it would be quite a problem if a head clog goes unnoticed even on just a 24h recording. I have 3 or maybe 4 SONY Time Lapse VCRs in storage, IIRC all of them has real time monitoring, while none of them were made by Sony, they are all rebadged from different OEMs. One of them I suspect being JVC, one maybe Mitsubishi (or that one is also JVC), and an other one was surely made by Sanyo. The Sanyo one is a monster, it has a really sturdy transport with ball bearings for the capstan, which I've never seen before. All of them can play back ordinary VHS recordings, but interestingly enough none of them has the VHS logo on it anywhere. Probably a licensing thing, they can't put the VHS logo on them if they can't record in the ordinary VHS format.
@@12voltvids already had the email scam happen to me, pulling it to a subscription service. So much for the idea the internet was going to be a 'free environment'. Its become a sinkhole for the greedy
@@12voltvids I can relate to that, had the same old email since 1995 and my ISP sold out the mail service to a pay per month service. Just $hits me but it's now how the world is wired. Everything tech is pay to use now
Thanks for showing us this Dave, yeah it's rather amazing who thought this up. I have a Sony DCR-IP1E MicroMV Handycam in to replace the LCD ribbon flex cable. I bet that has small heads compared to VHS.
Great vid, certainly the closest I've ever seen a head. They look so simple but I guess the tricky bit is getting everything perfectly aligned. It's sad that all the technology, jigs , machines and know how to make them is gone, (I assume). Would be interesting if it were impossible to store video digitally on memory sticks, how much further digital video tape recording technology would have advanced, and what picture quality it would yield. Judging how LTO tape technology went from storing 100Gb in Gen 1 in 2000 to 18Tb in Gen 9 just 2 decades later, I'm guessing quite a bit. After all LTO is 1/2" tape.!
Well we got for a short time, staying in the VHS world, digital VHS with MPEG2 and the lesser known W-VHS (~16:9 analog format with true high resolution). These were big machines at that time but technology would have reduced all this indeed.
Cool shots of the heads! I have wondered how many heads my JVC S-VHS machine would've had, since it did SP and LP as well as HiFi audio and, of course, S-VHS and VHS. Not NTSC, though. But at the time that wasn't an issue .
I think the grooves are there for creating an air cushion, so the tape is not rubbing on the cylinder all the time. It' s kind of an air bearing. Just a guess, though - I' d like to dig more into that rabbit hole.
Yes, that's why the groves are three. On the beta head the drum doesn't spin however, but air still gets pushed out the slot by the heads whizzing around inside and that provides enough of a cushion, plus the surface is rough. When the upper drum gets polished by the tape it starts to stick and then problems start
The shortest wavelemgth tbay can be recorded is mor than half the width of the gap. I repair broadcast quad videotape machines where the heads are rotating at 14,400 rpm!! Imaging the g-forces on the heads! Becuase od this speed, the headwheel rotates in air bearings. The rotary fransformer was invented by AMPEX. This elimimated brushes on the shaft which introduced noise in the picture. The quad videotape machines have 4 heads that are 90° apart. The heads protrude from the headwheel and is called "Tip projection" the heads actually dig into the tape as it is playing or recording. During rewind of fast fwd, the tape is pulled away from the heads. Professional quad heads only last 500 hours. There are still some people that hand wind the heads! Did you know that the word "videotape" was copywrited by AMPEX? RCA had to call ot "television tape"
Just like video cassette was a trademark of Sony. The video heads on all video recorders dig slightly into the tape. Yes I am aware quad ran on air bearings at 14400 rpm. Dv runs at 9000, and used a 1/4" tape.
They are not recessed. They atick out and plow along the tape surface making direct contact and they wear constantly. Life is about 1000 hours. Thats the average but they can last anywhere from 1000 to 4000 hours. As I mentioned that new one was for my time lapse machine and I generally had to replace it every 6 to 8 month so thats 4 to 5k hours running 24/7. This is why all vcrs came with 1 year warranty 90 days on the heads as someone that ran their machine 6 hours record 6 hours play every day could easily wear the heads in a year. I changed thousands of video heads. On average about 10 a week.
@@lakinnenlako6883 It's the drum that is (mostly) not in contact with the tape, because those grooves create an air cushion between the drum and the tape. The head chips are indeed in tight contact with the tape. The cutout on the drum is a lot longer and wider than the head chips themselves, so the air cushion between the drum and the tape collapses where the head chips are, effectively "sucking" the tape towards the head chips, which are not recessed, but a wee bit protruding. You can notice the wear on head drums with naked eye around the cutout for the head chips. On worn drums, the corners and edges of the cutout are rounded compared to the sharp edges of these cutouts on new drums.
It would be interesting to know how wide the heads are -- how wide of a track they record. Some late-model NTSC VHS machines have EP heads that are claimed to be 19 µm wide. Each recorded video track on EP would therefore be exactly 19 µm wide. Usually, the EP heads are used for LP-mode playback and recording, but these machines will not record in LP because, with a 19 µm head and LP's track pitch of 29 µm, the video tracks on LP would be the same width as on EP and would not record any additional information, thus not yielding higher quality. To make LP-mode recording worthwhile, the heads would have to be wider than 19 µm. My Panasonic machine apparently has 26 µm EP heads, so it _does_ support LP-mode recording. Another question is about the width of the SP heads. The track pitch of SP is 58 µm. Early-model four-head machines (mostly made by JVC) had SP heads that were 58 µm wide, but I have heard JVC later had to use narrower heads because other machines recorded with narrower heads on SP, resulting in JVC's wider 58 µm heads picking up a lot of noise. Is that true? According to Mr. Betamax's website, Betamax video heads are either 27 µm wide (for two-head machines and four head machines on βII and βIII) or 39 µm wide (for four-head machines on βI/βIs). The track pitches of βI, II, and III are coincidentally the same as those of VHS's three speeds -- 58, 29, and 19 µm.
Vhs sp was actually 66 micron tracks but most machines used 58 so there was a slight guard track. 26 was the standard for ep but the tracks were typically 22 microns as 66/3 is 22 so 26 heads have slight overlap. Some companies used 19 micron heads to improve ep performance. The big problem is recording at sp speed on a 2 head machine. You have skinny tracks and a bunch of space between tracks. That makes for poor Snr on 4 head machines. Another reason jvc opted for 48 micron sp as opposed to 66. Beta was difference. Beta typically only used 2 or 3 heads. 4 heads were initially on slhf900. One pair for record and play and the other for slow and fast play. When. The beta1 speed returned they put on wider heads for b1 as it improved signal to noise. Beta 1 super hi band looked every bit as good as 3/4" umatic. It really looked good, but went through tape fast. L500 only ran 60 min and l750 90. I don't miss tape, but beta was my favorite and I do have hundreds of tapes in storage I really need to digitize or put on DVD.
@@12voltvids I'm curious where you got 66 for VHS SP. I remember doing the math back in 1987 and getting 58 point something so I tried it again earlier tonight and got 58.16 microns max track width without overlap (max head width). If the speed is 33.35 mm/s (which I got out of an old book on VHS repair that I have) and divide by 59.94, the number of fields in a second, then you end up multiplying this by sqrt (1.0 - (cos 6 degrees)^2) , due to the 6 degree slant and the pythagorean theorem, the 58.16 number appears. I was thinking PAL would be wider and if I substitute 50 fields per second for 59.94, I get 69.72, which is closer to your 66, but I've heard that PAL SP is not the same speed on VHS as NTSC SP, so that would made it less, right? I'm curious.
@@3Cr15w311 You're right that track width on VHS SP was 58 microns, but heads were wider that that. During recording, the recording head was actually erasing a portion of the previous just recorded track. Why was it done? Why not 58 micron heads, you might wonder? It's because of a still picture. If the tape was stopped but drum still spinning, the track angle would skew and head would be crossing from one track to another. That would make head reading one track, then reading rubbish (mixture of two adjacent tracks - displayed as a wide horizontal noise bar on a screen), then reading the next track. Even worse, two adjacent tracks are different fields of interlaced picture with timing moved exactly one-half of a line, which would mess up the TV's horizontal deflection circuitry and make further mess of a still picture. What is done to prevent that? That's right - misalignment! Each head had azimuth angle of 6 degrees in opposite direction of the other, so heads are mutually misaligned by 12 degrees, so one head reading the track of the other head would read just noise. So, during still picture head would cross to adjacent track but would not read information from it. So, the only important thing for getting good stills is the correct tracking. (EDIT: I didn't answer why heads were wider than tracks: to make them read at least some of its tracks even during crossing the opposite track. If they had the same width as the track, the signal would drop completely during crossing the opposite track (resulting in a wide horizontal snowy bar at the screen).
Still, signal strength diminishes during crossing, so to get good stills one additional head is required - a head that would be placed very close to one of two main heads. So, you get THREE head VCRs, where the third head was used ONLY for stills and picture searches. The third head had the opposite azimuth and was moved off track - exatly what was needed. However, engineers got the idea - what if we put another head, i.e., the fourth one. Well, if you already have three heads, it wouldn't be much of a hassle. Two additional heads could be narrower, enabling double-lenght recordings (i.e., LP mode). Narrower heads would still read SP information good enough to enable good stills and picture searches. (And you always wondered why three-head VCRs had better stills than four or six-head VCRs in SP mode?) (There isn't much difference between 4-head and 6-head VCRs when it comes to picture. 6-head VCRs used 4 heads for picture and two heads for HiFi stereo (audio) only)
Philips was the master of stills, they had a series of U-matic VHS VCRs built in the late 80's that had noseless still, noiseless 2x playback and noiselss 1x REVERSE playback. Those VCRs had only TWO heads in a drum! even top-of-the shelf prosumer Panasonics (like NV-FS200 - their top model) couldn't do it! How Philips did it, I have absolutely no idea! JVC went a step further: they made video-drums with adjustable azimuth! They called it "Dynamic drum system" (e.g. HR-S8600EU). They installed a small servo motor that could physically tilt the drum. During stills or picture searches, their drums tilted to match the exact track angle. I've never seen them in real life, but I believe their stills were best that a VHS or S-VHS could offer. We could call it "VHS systems last stand", but, unfortunately, it came too late - when VCRs were already dying. Some prosumer machines, like Grundig GV-280S (early 90's?) had a different solution - a digital memory to store a picture frame. But that's a totally different story.
Very Cool Video. I'd still like to see a video explaining how the sigals are transferred from the spinning drum to the stationary drum on playback and vice versa in recording mode contactlessly? I still havent been able to find a good understandable explanation of this Rotary Transformer technology.
Rotaty transformer is just rings of wire one on the rotating side and the other on the stationary side. The heads pick up the fm signal recorded and pass it to the transformer winding. A magnetic field is created and it transfers to the other winding.
Great video on the details of the head. What Microscope do you use? Trying to find one for electronics repair and I can't find anything good but not expensive.
So is the Betamax drums which has the peekaboo chips on the spinning disk are both upper/lower drums smooth or would they have 'grooves' for the tape travel? I suppose Betas peekaboo drum design probably wouldn't have been suitable for the high speed winding seen in current vhs machines. Interesting the first drums wernt hard wearing which resulted in the thumping phenomenon until more robust drums were made. And would it have been better to have followed that peekaboo design thus eliminating manufacturing fat upper drum video heads?
All betamax wind and rewind the tape laced. Always have, except Sanyo. The slot was the original design from the reel to reel 1/2 machines from the 60's. The idea about the upper drum spinning was to reduce the need for critical alignment. The best design was the spinning wheel in the middle with stationary upper and lower drum, but that design required critial escentricity alignment when changed, with a special micrometer required to do the job.
Hi 👋 good morning nice videos you have ,I enjoy watching them,I have a MAGNAVOX VHS HQ COMBO ,DVD RECORDER/VCR ZV427MG9,the problem with it is the DVD recorder section is not working when I press open/close the door doesn't open it was working awhile back I had it in storage for about 2 yrs now ,I decided to play some dvd's but it won't open the VHS section is working ,can you shed some light on this please ,thanks in advance
The same. Digital recording isn't any different. Instead of analog signal modulating an fm carrier the digital bits modulate it. The head drum runs faster. In the case of digital 8 the head drum runs 2.5x faster. My betacam sx player can play both digital sx format tape and analog sp tapes.
I never said dvhs ran faster. I said digital 8 did. Digital 8 recorded 25m bit dv stream which is all I frames (full frames) dvhs was mpg2 ipb long gone if I remember. Never saw a dvhs, never worked on one. I actually never even saw one in a store and I did look for them.
Bond wires? Thats just the head coil wires soldered to the pcb. I would like to see the inductance of the heads. And why are the coils are different amount of turns on each side of the "U" shape? Thanks for sharing.
@@12voltvids what about: 1: I would like to see the inductance of the heads. 2: And why are the coils are different amount of turns on each side of the "U" shape?
I. Simple terms to match the impedance of the rotary transformer. I went into more detail but it didn't save and I don't feel like typing it our again.
Actually it's 4 head drum, the vhs drum. Thats a double azimuth head. One one side the sp a field and ep b head and the other the sp b and ep a. Tbe beta head was a 2 head drum. Of course each head has 2 poles. That is the gap where the magnetic field is produced.
How much money do you have? Fabricating a 1 off video head you are talking tons of money. Know a guy in the obsolete format recovery business. He had an odd ball 1" tape that had been recorded on a 2 head boach helical. Now the common format used was type A and then they settled on C format. Thatvuaed a 360' wrap and the scanner had a flying erase head a record head and a playback head (at least machines that jad dynamic tracking like the ampex vpr1 did) machines without dynamic tracking had a single record / play head. Bosch used a 180' wrap and 2 heads. Anyway he found an old machine but the heads were trashed. He searched and found a place in LA that could make him a new scanner, for 50 000.00. Needless to say he didn't do the job be referred the client to a place in the states that charged 1000 per hour to transfer the tape. The client laughed. Figured they could get this old tape done for 100 bucks.
I made a good living out of cleaning and reselling VHS machines in the 80's~90's, because clueless tight-fisted consumers would sooner replace cheap supermarket VCR's, than pay someone £50+ to repair them. When in reality, a piece of white photocopy paper and a dab of switch cleaner gently applied to the drum surface while spinning, more often than not, work a treat. 👍 Kids and their sticky fingers eh! 😆
@@_innerscape_ Probably because both head gaps need to be at the closest possible spot to each other, in order to the head switching point be correct for both the SP and the EP heads.
@@_innerscape_ Oh... Well, it must be some kind of wizardry... on the dual azimuth heads, what I said regards to the head switching point, probably makes sense, but on the Beta head, I don't know what's the reason. Can be a bandwidth or saturation thing, or maybe the tape makes better contact with the head at that spot.
There are no LP heads. Never were, LP was never a licensed VHS speed only SM and EP. Panasonic went rogue and introduced a speed that was never an offical speed. LP used the EP head and did not provide any picture improvement over EP.
@@12voltvids I'd say, from the tapes I've archived, picture quality looks worst on LP than on EP. But, my region is complicated in that department, because there was never an official support for EP speed in our case.
@@12voltvids How about LP and EP on 2 head machines? In 1986, My parents bought a Sears VCR with only 2 heads that supported all speeds and LP did look better than EP on that machine so I figure it was using compromise width heads that lowered SP quality somewhat but made LP and EP work better. I made a good many LP recordings on it. It was one of those strange 2 head no frills video machines but with Dolby B on stereo linear tracks (no HiFi). Did any machines record LP and EP with full-width 58 micron heads or did they use some compromise like something between 30 and 50? I remember reading that they were able to align the pulses on EP so that even if tracks overlapped, things would be OK, but on LP they couldn't but somehow they'd "cancel out". I'd love to hear you explain that if it's the case. I'm specifically interested in those early to mid 1980s machines.
2 head machines typically had 22 micron heads which was the track width of ep. 68 is full track width of sp. Some early panasonic / rca machines with just sp/lp had 42 micron heads. The narrower heads will record just fine at faster speeds. There will be blank tape between the tracks. This wasted space reduces signal to noise ratio. As far as overlap yes the next head will partially erase however the recording is azimuth recorded. So the angle is different. Also the signal is fm recorded.
Things were serviceable that time...china and mobile electronics ruined everything....once your mobile dead 90 percent chances you lost your data and precious memories...nearly everyone's faced it several time....but noone talking about this issue....govt must make a rule that mobile companies must design their product such a way that ..person able extract data even mobile is dead...its tecnically easy task for compnies...they can use detachable emcc card in mobile...
You can force companies hands by refusing to buy a phone that doesn't not have an sd card. I have a Samsung s9 and continue to use it because of that. My spare is an s20fe which is the last with sd. Next one after that will be a different brand I guess. Unless Samsung brings back sd card If everyone e took that attitude and didn't cave in and buy their phones either removable memory and actually told the companies this is the reason they are not buying their product and they would change things. Same for cloud storage. Just say no.
I think we should pay respect for the engineers of the day that made this thing possible, it is brilliant engineering at it's best.
VCR's should not be taken as granted because a lot of thinking and designing went into them starting from the VTR's of the 50'.
And they could do it for sale at consumer prices.
@@hugh007 which also helped doom the industry, as servicing the units became economically unfeasible. Then, digital storage entered into the picture and put the final nail into its coffin.
Beyond hardware failures, like belts failing, just cleaning video heads, one would look at the cost of paying a tech vs sandpapering, erm, I mean a "cleaning tape" to abrade the heads clean and call it done and wonder what happened to the video quality. It was literally like cleaning your car by using sandpaper. A belt failed, landfill it and replace the machine.
Gave up the field around '98 when everything in consumer electronics became completely disposable and went into IT. While the computers may be reaching a similar state, networking and data transfer remain economically viable. I'd started repairing consumer electronics for a living in 1980, learning VCR's, then CD's, DVD's, etc as they came along. Repaired to component level everything from vacuum tube circuits, hybrid vacuum tube and bipolar transistor based circuits, later incorporating integrated circuits, VLSI when it ambled along, comb filter IF's until the industry essentially collapsed and IT was growing.
Now, well I just looked up to see if VCR's are even still being sold and I was a touch surprised to find that they are.
I've been storing video on hard drives, with backups and important videos go onto a RAID array. Drive fails, there's a spare to automagically switch in and rebuild the array while a replacement gets installed.
More amazing is to see the machines that wound those heads. Tiny ferrite chip heads, wound with tiny wires thinner than a human hair, manufactured in bulk. That in and of itself is a major accomplishment in technological handling of components! Manufacturing to submicroscopic tolerances, another major accomplishment.
Thank you for this demonstration. I find it amazing that such precision and tiny engineering was possible these days at a price that was relatively affordable. In addition they have made this serviceable, which is a lot more than you can say about modern electronics today where the service guy is treated like the enemy of these modern manufacturers
Manufacrure are not interested on service. That costs money. They just want to design and build.
I came across a magazine called Video Repair or something. I think it was a late 1980s or maybe early 1990s issue where there was an article basically saying that VCRs and other video equipment had become so cheap that the economics of repair would not work anymore. The article suggested switching to quick diagnostics of which sub-assembly is at fault, and replacing complete sub-assemblies instead of repairing each tiny thing like a head on a drum. I guess this worked when parts were cheaper than a complete unit. Nowadays I can buy a new phone for less money it costs to replace the glass on the screen. But I am keeping my 2013 MBP, had battery changed recently. Damn Apple glues more things together from generation to generation, making it less repairable despite the whole "Right to Repair" hoopla. Tesla does not even allow anyone but Tesla techs to work on their cars.
@@12voltvidsi have a 8mm video tape that has specs in and outside of the reels, when i fast forwarded the tape, some dissapeared, but theres still stuff on the inner reel that did not stick or stay on the tape. Is that mold or some sort of plastic mark?
There's an important concept you need to understand, it's called "economy of scale".
It probably was expensive to design and manufactuer the first couple units, but once they had a market scaling up production made a huge difference.
Individual units cost a lot less when you're making tens of thousands of them and the expenses of dedicated machinery are swallowed up by the revenue stream.
@@12voltvids You need human beings to provide support and servicing, people are expensive. And you can't turn off human employees when you aren't using them/benefiting from the work they do.
What’s even more amazing is the transformer coupling of the signal out!
What’s really amazing is the timing of everything and how the tape is moved against the head. The fact that the head moves in a helical fashion across the tape (head is angled and spins diagonally across the tape). That is some clever control and servo systems for sure.
That js what the control track is for.
@@12voltvids not quite on its own. The control track itself is quite broad and low frequency. Servo tolerances were tight out of necessity, as were mechanical tolerances. At the time videotape was introduced, such tolerances were literally unheard of in consumer goods of any sort.
In a very real way, they were practice for the development of yet to come optical media, with its even tighter tolerances. And the components themselves in just the mechanical, think about it, one's recording on what's literally an abrasive, yet somehow the guide rollers and drum proper didn't get abraded out of tolerance or as bad, polished until stiction became a tape fixating problem. The heads actually penetrating the oxide layer slightly and not swiftly wearing out. That's a *lot* of metallurgy and mechanical tolerance knowledge being applied - then the servos can come into play.
Yeah, used to repair these, initially picking them up on my own as televisions started to move toward becoming disposable. Became proficient in VCR's and as their prices plummeted, moved into CD and DVD service... Industry grows, one grows or stagnates into poverty, I just grew and learned how the device operated to its lowest levels, which gave me an edge on peers that couldn't comprehend those devices fully.
Always did get a chuckle over those who just refused to learn. They'd never figure out a problem in a PLL or even an SMPS and I'd get to eat their lunch. Tried to show some, but if they really didn't have an interest, they'd never learn.
I often inspect heads under a microscope like this. Surprisingly perhaps, it's not easy to spot head wear, completely worn out heads usually look fine. But damaged heads can sometimes be seen. V2000 format heads are interesting as they sit on piezo electric actuators (as do some Betacam and MII ones I believe).
@@video99couk And all of the 8mm formats, probably miniDV and even DAT uses piezoelectric tracking. Sony licenced the technology from Philips' V2000 format when they were developing the Video8 system.
The Mitsubishi hsu82 also had dynamic tracking heads for trick playback.
This one reminds me of my first Beta VCR that I bought when I was around 12 years old. It came with a box of tapes. I was so excited! The picture quality wasn't great though and the internet didn't exist, so I tried to clean the heads myself without much clue, and the result must have been what you showed here with the broken head. Nothing but snow was my reward after that 'cleaning'. An early life lesson though!
Just wait for the next one where I will attempt to transplant a drum from an old UMatic playback only machine to that VO5850 that had the open coil. Wish me luck. I'll edit that as soon as my computer is available, which it isn't now because I went to the airshow yesterday and took some pictures of old airplanes doing tricks. 4K video takes forever for my old PC to deal with. 12+ hours to render out less than a 60 minute program. File size will be about 100 gigs LOL
Definetely interesting video, never seen these actual video heads this close before, so thanks for doing this video :)
And a beta head the tape was wrapped almost all the way around, versus a VHS only half. I worked on them for years in the 80’s…thanks for the trip down memory lane 🙏👍
The tape was in contact for the same 180'. Just beta pulled more tape out using a U loading system just like the professional systems. This resulted is less bending of the tape, resulting in lower tape tension which allowed the tape to stay threaded. Until the mid 90s all vhs unloaded the tape to ff and rewind. This was due to the design. They had to make several changes to allow vhs to remain loaded and this added more points of failure like the pinch roller that lowers down on the back side of the tape. Beta was better in every way except marketing and that Sony wanted it to be profitable whereas jvc just wanted to give it away. I think if one were to look at profit margin on each beta /betacam unit sold Sony came out on top. Their professional betacam format very quickly became the field production source for production. If you saw it on TV shot between 1982 and 2015 there js a very good chance it was shot and edited on betacam, betacam sp, betacam sx, digibeta or hdbeta. It was pretty much the only format used. That professional format grew from home betamax and betamax evolved from 3/4 umatic.
It's a miracle these things work at all. Looks like some garage project. Amazing you can get a high quality video signal from something that looks so ungainly and crude looking.
The edge of that drum looks like it should instantly shred any tape laid upon it while it is spinning.
Just awesome. Never imagined such amazing engineering at miniature level. Great video
Makes sense why they were so expensive in the 80s! Thanks for showing us.
Very interesting, good to see them close up ,thanks.
Vcr porn
I remember the first family vcr. Not a clue about them, I looked inside through the tape slot and thought why is the big motor on such an angle 😂. Since then I had a fascination how vcrs work and am still amazed by the way they recorded and played back tape.
Well I actually looked at a VHS drum I'm having floating around after watching this video, through a vintage optical kit microscope, that has about the same magnification, or maybe a bit more. I looked at a stereo cassette tape head too first. I could notice what a schematic I found on the internet calls 'index error', that's a tiny 'shift' between the two poles of each heads perpendicular to the tape direction, as well as on the shielding plate between the two heads, but not unexpectedly, I could not see the gap itself, even at that magnification. And then I looked at the video heads, making sure that some light shines off them, so I can see the edge of them that's facing the tape, properly. I could clearly see a narrowing in the middle of both of them, I assume those narrowings define the effective width of the tracks that these heads record and play. At no moment I could be fooled that what I see is the gap itself, if those were, they would be far too wide. Needless to say I just couldn't make out the actual gap on those, again, not unexpectedly. Those are *extremely* narrow gaps, that normally the magnetic field would have *no problem* whatsoever jumping through, but there's a very thin gold spacer in those gaps. Gold is diamagnetic, it pushes magnetic field out of itself. So far I found no data on the size of the gap, but it must be anywhere between just a few micrometers down to a few nanometers. That's really just my broad guestimation.
Right now I can't find any source on the gold layer or foil, but maybe you heard of it. I just don't remember where I read about that.
The narrow part is the track width, the actual gap is much smaller than that typically only a few microns. Would need a much higher power microscope than this to see the actual gap.
@@12voltvids - Ok, I found back this info about gold on the wiki about heads. D'OH!
Fascinating. Seeing it this close really helps understand how it works. Thanks.
How the hell did they wind the wire on those! Can't get an idea to how small those really are from the video.
I always thought the secret sauce was actually the metal disc with the concentric circles. I never knew there was tiny coils mounted to the edge. Thanks for the lesson.
Back in the early 90s I replaced the heads on a few VHS machines. Not the whole drum though. I was swapping out heads from different machines that were broken and a couple times I was able to purchase heads I needed from a local repair shop. Somewhere I had found documents that showed most makes/models and which ones used the same heads, and with their part #s. That helped out a lot being pre internet. My old eyes would need that microscope today though. Lol
And thanks for showing the Beta head! I'd never seen one of them up close. Interesting in how the two types compare.
Normally the entire drum wasn't changed. Just the upper drum. Never the individual heads.
@@12voltvids it is doable, though time consuming and tedious! That is probably why the whole drum was replaced. Plus replacing the whole upper drum made repair shops more money.
I can't see the width difference of the head chips, probably because this is a time lapse head drum. Time lapse VCRs use two sets of the same width head chips (probably EP width), one set for recording, one set for real time monitoring off tape. This is necessary to prevent creating a week worth of failed CCTV recording when a head clogs.
Also this looks like quite a garbage quality aftermarket head. The head chips seem chipped at the gap, there's hardly any material left on one of them.
Thanks, this is an interesting video, I'm continuing now from the 6:40 mark where I paused to write this comment.
There is/was a Czech guy on YT who hand wound video head chips under a microscope. He done that for big 1...2 inch studio VTRs, IIRC he removed head chips from VHS drums by dissolving the epoxy, glued the chip on the VTR's head and wound it with a set of super fine tip tweezers. It was incredible. I subscribed on his channel about a decade ago, now I can't find him, maybe they removed the channel because he showed TV footages that might have caused him multiple copyright strikes. I'm sorry I haven't downloaded at least some of his videos. I was glued to the screen, despite I couldn't understand a single word.
Only if I commented a few seconds forward into the video... So it isn't the whole chip that is of video track width, they are only narrowed down at the gap. Makes sense, if the whole chip would be 22um width, it would be very fragile, probably impossible to mass produce.
It wasn't a time lapse. It was a real time that could operate in 2H or 24h. Basically there was an alarm input. Close the contact and it kicks to 2h. The head was a standard 4 head for mitsubishi vcr. The quality of the 24H speed wasn't bad and you could play the tape back on the machine but if played on a regular machine it played 4x normal speed. It used 19 micron heads and you can see the difference on camera. You might be looking at the wrong place.
@@12voltvids Yep, I expected the whole EP head chip to be much narrower, but instead it is only really narrower around the gap. Did your CCTV VCR had real time monitoring? It is a must IMO, because it would be quite a problem if a head clog goes unnoticed even on just a 24h recording. I have 3 or maybe 4 SONY Time Lapse VCRs in storage, IIRC all of them has real time monitoring, while none of them were made by Sony, they are all rebadged from different OEMs.
One of them I suspect being JVC, one maybe Mitsubishi (or that one is also JVC), and an other one was surely made by Sanyo. The Sanyo one is a monster, it has a really sturdy transport with ball bearings for the capstan, which I've never seen before. All of them can play back ordinary VHS recordings, but interestingly enough none of them has the VHS logo on it anywhere. Probably a licensing thing, they can't put the VHS logo on them if they can't record in the ordinary VHS format.
I wondered why head surface was ruff - I agree Amazing tech - Thanks
I'm getting Regular Show Format War vibes, I miss these old format machines, changed out just to make consumers change formats
What's worse js now big tech js squeezing us to upgrade computers by threatening to cut off our email
@@12voltvids already had the email scam happen to me, pulling it to a subscription service. So much for the idea the internet was going to be a 'free environment'. Its become a sinkhole for the greedy
@@12voltvids I can relate to that, had the same old email since 1995 and my ISP sold out the mail service to a pay per month service. Just $hits me but it's now how the world is wired. Everything tech is pay to use now
Thanks for showing us this Dave, yeah it's rather amazing who thought this up. I have a Sony DCR-IP1E MicroMV Handycam in to replace the LCD ribbon flex cable. I bet that has small heads compared to VHS.
I was replacing the head wearing white gloves like an appraiser.
Great vid, certainly the closest I've ever seen a head. They look so simple but I guess the tricky bit is getting everything perfectly aligned. It's sad that all the technology, jigs , machines and know how to make them is gone, (I assume). Would be interesting if it were impossible to store video digitally on memory sticks, how much further digital video tape recording technology would have advanced, and what picture quality it would yield. Judging how LTO tape technology went from storing 100Gb in Gen 1 in 2000 to 18Tb in Gen 9 just 2 decades later, I'm guessing quite a bit. After all LTO is 1/2" tape.!
Well we got for a short time, staying in the VHS world, digital VHS with MPEG2 and the lesser known W-VHS (~16:9 analog format with true high resolution). These were big machines at that time but technology would have reduced all this indeed.
Cool shots of the heads! I have wondered how many heads my JVC S-VHS machine would've had, since it did SP and LP as well as HiFi audio and, of course, S-VHS and VHS. Not NTSC, though. But at the time that wasn't an issue
.
2 sp, 2 ep, 2 hifi. If it had flying erase it would have had 2
I think the grooves are there for creating an air cushion, so the tape is not rubbing on the cylinder all the time.
It' s kind of an air bearing. Just a guess, though - I' d like to dig more into that rabbit hole.
Yes, that's why the groves are three. On the beta head the drum doesn't spin however, but air still gets pushed out the slot by the heads whizzing around inside and that provides enough of a cushion, plus the surface is rough.
When the upper drum gets polished by the tape it starts to stick and then problems start
Great vid 🥰
The shortest wavelemgth tbay can be recorded is mor than half the width of the gap.
I repair broadcast quad videotape machines where the heads are rotating at 14,400 rpm!! Imaging the g-forces on the heads! Becuase od this speed, the headwheel rotates in air bearings.
The rotary fransformer was invented by AMPEX. This elimimated brushes on the shaft which introduced noise in the picture.
The quad videotape machines have 4 heads that are 90° apart. The heads protrude from the headwheel and is called "Tip projection" the heads actually dig into the tape as it is playing or recording. During rewind of fast fwd, the tape is pulled away from the heads.
Professional quad heads only last 500 hours.
There are still some people that hand wind the heads!
Did you know that the word "videotape" was copywrited by AMPEX? RCA had to call ot "television tape"
Just like video cassette was a trademark of Sony.
The video heads on all video recorders dig slightly into the tape. Yes I am aware quad ran on air bearings at 14400 rpm. Dv runs at 9000, and used a 1/4" tape.
I still don't get it - how does it wear out if the tape spins on drums and heads are recessed? Is the drum getting worn out?
They are not recessed. They atick out and plow along the tape surface making direct contact and they wear constantly. Life is about 1000 hours. Thats the average but they can last anywhere from 1000 to 4000 hours. As I mentioned that new one was for my time lapse machine and I generally had to replace it every 6 to 8 month so thats 4 to 5k hours running 24/7.
This is why all vcrs came with 1 year warranty 90 days on the heads as someone that ran their machine 6 hours record 6 hours play every day could easily wear the heads in a year. I changed thousands of video heads. On average about 10 a week.
@@lakinnenlako6883 It's the drum that is (mostly) not in contact with the tape, because those grooves create an air cushion between the drum and the tape. The head chips are indeed in tight contact with the tape. The cutout on the drum is a lot longer and wider than the head chips themselves, so the air cushion between the drum and the tape collapses where the head chips are, effectively "sucking" the tape towards the head chips, which are not recessed, but a wee bit protruding. You can notice the wear on head drums with naked eye around the cutout for the head chips. On worn drums, the corners and edges of the cutout are rounded compared to the sharp edges of these cutouts on new drums.
Ok. Thanks for explaining.
Excellent! Thank so much for sharing this with us. Details on the microscope you are using?
It would be interesting to know how wide the heads are -- how wide of a track they record.
Some late-model NTSC VHS machines have EP heads that are claimed to be 19 µm wide. Each recorded video track on EP would therefore be exactly 19 µm wide.
Usually, the EP heads are used for LP-mode playback and recording, but these machines will not record in LP because, with a 19 µm head and LP's track pitch of 29 µm, the video tracks on LP would be the same width as on EP and would not record any additional information, thus not yielding higher quality. To make LP-mode recording worthwhile, the heads would have to be wider than 19 µm.
My Panasonic machine apparently has 26 µm EP heads, so it _does_ support LP-mode recording.
Another question is about the width of the SP heads. The track pitch of SP is 58 µm. Early-model four-head machines (mostly made by JVC) had SP heads that were 58 µm wide, but I have heard JVC later had to use narrower heads because other machines recorded with narrower heads on SP, resulting in JVC's wider 58 µm heads picking up a lot of noise. Is that true?
According to Mr. Betamax's website, Betamax video heads are either 27 µm wide (for two-head machines and four head machines on βII and βIII) or 39 µm wide (for four-head machines on βI/βIs). The track pitches of βI, II, and III are coincidentally the same as those of VHS's three speeds -- 58, 29, and 19 µm.
Vhs sp was actually 66 micron tracks but most machines used 58 so there was a slight guard track. 26 was the standard for ep but the tracks were typically 22 microns as 66/3 is 22 so 26 heads have slight overlap. Some companies used 19 micron heads to improve ep performance. The big problem is recording at sp speed on a 2 head machine. You have skinny tracks and a bunch of space between tracks. That makes for poor Snr on 4 head machines. Another reason jvc opted for 48 micron sp as opposed to 66. Beta was difference. Beta typically only used 2 or 3 heads. 4 heads were initially on slhf900. One pair for record and play and the other for slow and fast play. When. The beta1 speed returned they put on wider heads for b1 as it improved signal to noise. Beta 1 super hi band looked every bit as good as 3/4" umatic. It really looked good, but went through tape fast. L500 only ran 60 min and l750 90. I don't miss tape, but beta was my favorite and I do have hundreds of tapes in storage I really need to digitize or put on DVD.
@@12voltvids I'm curious where you got 66 for VHS SP. I remember doing the math back in 1987 and getting 58 point something so I tried it again earlier tonight and got 58.16 microns max track width without overlap (max head width). If the speed is 33.35 mm/s (which I got out of an old book on VHS repair that I have) and divide by 59.94, the number of fields in a second, then you end up multiplying this by sqrt (1.0 - (cos 6 degrees)^2) , due to the 6 degree slant and the pythagorean theorem, the 58.16 number appears. I was thinking PAL would be wider and if I substitute 50 fields per second for 59.94, I get 69.72, which is closer to your 66, but I've heard that PAL SP is not the same speed on VHS as NTSC SP, so that would made it less, right? I'm curious.
@@3Cr15w311 You're right that track width on VHS SP was 58 microns, but heads were wider that that. During recording, the recording head was actually erasing a portion of the previous just recorded track. Why was it done? Why not 58 micron heads, you might wonder?
It's because of a still picture. If the tape was stopped but drum still spinning, the track angle would skew and head would be crossing from one track to another. That would make head reading one track, then reading rubbish (mixture of two adjacent tracks - displayed as a wide horizontal noise bar on a screen), then reading the next track. Even worse, two adjacent tracks are different fields of interlaced picture with timing moved exactly one-half of a line, which would mess up the TV's horizontal deflection circuitry and make further mess of a still picture.
What is done to prevent that? That's right - misalignment! Each head had azimuth angle of 6 degrees in opposite direction of the other, so heads are mutually misaligned by 12 degrees, so one head reading the track of the other head would read just noise. So, during still picture head would cross to adjacent track but would not read information from it. So, the only important thing for getting good stills is the correct tracking.
(EDIT: I didn't answer why heads were wider than tracks: to make them read at least some of its tracks even during crossing the opposite track. If they had the same width as the track, the signal would drop completely during crossing the opposite track (resulting in a wide horizontal snowy bar at the screen).
Still, signal strength diminishes during crossing, so to get good stills one additional head is required - a head that would be placed very close to one of two main heads. So, you get THREE head VCRs, where the third head was used ONLY for stills and picture searches. The third head had the opposite azimuth and was moved off track - exatly what was needed.
However, engineers got the idea - what if we put another head, i.e., the fourth one. Well, if you already have three heads, it wouldn't be much of a hassle. Two additional heads could be narrower, enabling double-lenght recordings (i.e., LP mode). Narrower heads would still read SP information good enough to enable good stills and picture searches.
(And you always wondered why three-head VCRs had better stills than four or six-head VCRs in SP mode?)
(There isn't much difference between 4-head and 6-head VCRs when it comes to picture. 6-head VCRs used 4 heads for picture and two heads for HiFi stereo (audio) only)
Philips was the master of stills, they had a series of U-matic VHS VCRs built in the late 80's that had noseless still, noiseless 2x playback and noiselss 1x REVERSE playback. Those VCRs had only TWO heads in a drum! even top-of-the shelf prosumer Panasonics (like NV-FS200 - their top model) couldn't do it! How Philips did it, I have absolutely no idea!
JVC went a step further: they made video-drums with adjustable azimuth! They called it "Dynamic drum system" (e.g. HR-S8600EU). They installed a small servo motor that could physically tilt the drum. During stills or picture searches, their drums tilted to match the exact track angle. I've never seen them in real life, but I believe their stills were best that a VHS or S-VHS could offer. We could call it "VHS systems last stand", but, unfortunately, it came too late - when VCRs were already dying.
Some prosumer machines, like Grundig GV-280S (early 90's?) had a different solution - a digital memory to store a picture frame. But that's a totally different story.
♥ from PAL region.
Nice 👍🏻
I repaired consumer electronics for 23 years. Mostly VCR and camcorders.
I love this video.
Very Cool Video. I'd still like to see a video explaining how the sigals are transferred from the spinning drum to the stationary drum on playback and vice versa in recording mode contactlessly? I still havent been able to find a good understandable explanation of this Rotary Transformer technology.
Rotaty transformer is just rings of wire one on the rotating side and the other on the stationary side. The heads pick up the fm signal recorded and pass it to the transformer winding. A magnetic field is created and it transfers to the other winding.
@@12voltvids Thank You Sir.
Very interesting. I thought it was just a single piece with no gap
Fascinating
Yo tenia un Betamax de Sony pero, no en el 2003, grababa en esos bichos el año 1985
Great video on the details of the head. What Microscope do you use? Trying to find one for electronics repair and I can't find anything good but not expensive.
I just reviewed it last week.
So is the Betamax drums which has the peekaboo chips on the spinning disk are both upper/lower drums smooth or would they have 'grooves' for the tape travel?
I suppose Betas peekaboo drum design probably wouldn't have been suitable for the high speed winding seen in current vhs machines.
Interesting the first drums wernt hard wearing which resulted in the thumping phenomenon until more robust drums were made.
And would it have been better to have followed that peekaboo design thus eliminating manufacturing fat upper drum video heads?
All betamax wind and rewind the tape laced. Always have, except Sanyo.
The slot was the original design from the reel to reel 1/2 machines from the 60's.
The idea about the upper drum spinning was to reduce the need for critical alignment. The best design was the spinning wheel in the middle with stationary upper and lower drum, but that design required critial escentricity alignment when changed, with a special micrometer required to do the job.
@12voltvids it make me wonder why the early models the disc wasn't a tight fit compared to the later ones.
I'm expecting coils around cores,
I'll watch and see. I'm sure it will be cool .
Hi 👋 good morning nice videos you have ,I enjoy watching them,I have a MAGNAVOX VHS HQ COMBO ,DVD RECORDER/VCR ZV427MG9,the problem with it is the DVD recorder section is not working when I press open/close the door doesn't open it was working awhile back I had it in storage for about 2 yrs now ,I decided to play some dvd's but it won't open the VHS section is working ,can you shed some light on this please ,thanks in advance
Belt?
Now I'm wondering- what would D-VHS heads look like?
The same. Digital recording isn't any different. Instead of analog signal modulating an fm carrier the digital bits modulate it. The head drum runs faster. In the case of digital 8 the head drum runs 2.5x faster. My betacam sx player can play both digital sx format tape and analog sp tapes.
@@12voltvids Huh. My D-VHS drum seems to run at 1800... Would the heads be thinner?
I never said dvhs ran faster. I said digital 8 did. Digital 8 recorded 25m bit dv stream which is all I frames (full frames) dvhs was mpg2 ipb long gone if I remember. Never saw a dvhs, never worked on one. I actually never even saw one in a store and I did look for them.
Awesome
Bond wires? Thats just the head coil wires soldered to the pcb. I would like to see the inductance of the heads. And why are the coils are different amount of turns on each side of the
"U" shape? Thanks for sharing.
I was referring to the section of pcb that the head coil and lead wires were bonded for.
@@12voltvids what about:
1: I would like to see the inductance of the heads.
2: And why are the coils are different amount of turns on each side of the
"U" shape?
I. Simple terms to match the impedance of the rotary transformer. I went into more detail but it didn't save and I don't feel like typing it our again.
@@12voltvids thanks, I will look it up
I wonder hothe head gap lookswunder an electronic microscope.
2:03 disagree with most after this....One head has two poles. One "set" of heads for SP. This is a two-head drum.
Actually it's 4 head drum, the vhs drum. Thats a double azimuth head. One one side the sp a field and ep b head and the other the sp b and ep a. Tbe beta head was a 2 head drum.
Of course each head has 2 poles. That is the gap where the magnetic field is produced.
I wonder if it’s possible to have them rebuilt.
How much money do you have?
Fabricating a 1 off video head you are talking tons of money. Know a guy in the obsolete format recovery business. He had an odd ball 1" tape that had been recorded on a 2 head boach helical. Now the common format used was type A and then they settled on C format. Thatvuaed a 360' wrap and the scanner had a flying erase head a record head and a playback head (at least machines that jad dynamic tracking like the ampex vpr1 did) machines without dynamic tracking had a single record / play head. Bosch used a 180' wrap and 2 heads. Anyway he found an old machine but the heads were trashed. He searched and found a place in LA that could make him a new scanner, for 50 000.00. Needless to say he didn't do the job be referred the client to a place in the states that charged 1000 per hour to transfer the tape. The client laughed. Figured they could get this old tape done for 100 bucks.
That's cool 👍👍
I made a good living out of cleaning and reselling VHS machines in the 80's~90's, because clueless tight-fisted consumers would sooner replace cheap supermarket VCR's, than pay someone £50+ to repair them. When in reality, a piece of white photocopy paper and a dab of switch cleaner gently applied to the drum surface while spinning, more often than not, work a treat. 👍
Kids and their sticky fingers eh! 😆
What microscope are you using?
10:43 why the coils are asymetric?
@@_innerscape_ Probably because both head gaps need to be at the closest possible spot to each other, in order to the head switching point be correct for both the SP and the EP heads.
@@mrnmrn1 mmmh... Nope, I pointed at the Beta head, single purpose, not SP EP. One coil is wider, the other is thinner. Resonances? Wider bandwidth?
@@_innerscape_ Oh... Well, it must be some kind of wizardry... on the dual azimuth heads, what I said regards to the head switching point, probably makes sense, but on the Beta head, I don't know what's the reason. Can be a bandwidth or saturation thing, or maybe the tape makes better contact with the head at that spot.
The beta head has a chunk missing from it.
@@12voltvids Yep, I got that, I mean the actual copper coils mounted on that diapason-fork thingy. They're different, not identichal twins.
Gold wire or copper? On the head?
Copper, enamel insulated
❤❤❤❤❤❤❤❤❤❤❤priceless ❤❤❤❤
Broken head, probably from playing too many violent action films! 🤣
You wonder why so many disable comments and delete the stupid comments.
Where is the LP head? 😁
There are no LP heads. Never were, LP was never a licensed VHS speed only SM and EP. Panasonic went rogue and introduced a speed that was never an offical speed. LP used the EP head and did not provide any picture improvement over EP.
@@12voltvids I'd say, from the tapes I've archived, picture quality looks worst on LP than on EP. But, my region is complicated in that department, because there was never an official support for EP speed in our case.
@@12voltvids How about LP and EP on 2 head machines? In 1986, My parents bought a Sears VCR with only 2 heads that supported all speeds and LP did look better than EP on that machine so I figure it was using compromise width heads that lowered SP quality somewhat but made LP and EP work better. I made a good many LP recordings on it. It was one of those strange 2 head no frills video machines but with Dolby B on stereo linear tracks (no HiFi). Did any machines record LP and EP with full-width 58 micron heads or did they use some compromise like something between 30 and 50? I remember reading that they were able to align the pulses on EP so that even if tracks overlapped, things would be OK, but on LP they couldn't but somehow they'd "cancel out". I'd love to hear you explain that if it's the case. I'm specifically interested in those early to mid 1980s machines.
2 head machines typically had 22 micron heads which was the track width of ep. 68 is full track width of sp. Some early panasonic / rca machines with just sp/lp had 42 micron heads. The narrower heads will record just fine at faster speeds. There will be blank tape between the tracks. This wasted space reduces signal to noise ratio. As far as overlap yes the next head will partially erase however the recording is azimuth recorded. So the angle is different. Also the signal is fm recorded.
Things were serviceable that time...china and mobile electronics ruined everything....once your mobile dead 90 percent chances you lost your data and precious memories...nearly everyone's faced it several time....but noone talking about this issue....govt must make a rule that mobile companies must design their product such a way that ..person able extract data even mobile is dead...its tecnically easy task for compnies...they can use detachable emcc card in mobile...
You can force companies hands by refusing to buy a phone that doesn't not have an sd card. I have a Samsung s9 and continue to use it because of that. My spare is an s20fe which is the last with sd. Next one after that will be a different brand I guess. Unless Samsung brings back sd card
If everyone e took that attitude and didn't cave in and buy their phones either removable memory and actually told the companies this is the reason they are not buying their product and they would change things. Same for cloud storage. Just say no.
This is nothing compared with the harddisk head
No shit
Rolling shutter sucks ;-)
My Sony camera has a global shutter
microscope uses rolling shutter, my production cameras global shutters
@@12voltvids Yes, that is what I meant. Thanks!