Tough Repair Admiral 19A1 7JP4 Electrostatic Television Diagnosis Capacitors SMD Alignment
Vložit
- čas přidán 25. 08. 2023
- Lots of problems with this one tough to diagnose and figure out confusing problems and testing different capacitors in the deflection circuits. A long but interesting video following the leads
/ shango066 - Zábava
Nice of you to help young hobbyists. A TV technician taught me electronics in 1969, now I fix computers,, tablets and phones. It beat having a paper route at age 11.
Idk, a good subscription paper route in the 90's was pretty lucrative. As a kid in one year I made over $6000. I remember this because I had to report it to the IRS.
Never did it for a living, I was a cop then a lawyer, did it as a hobby over the years, and took it up again as a retirement hobby. It's hard to find old stuff to work on in Thailand where I retired. @@commodoresixfour7478
@@commodoresixfour7478 Had one in the early 70s, 40 customers would make maybe $10/wk, mowed yards for 3 customers, made as much as the route.
My father worked as quality inspector on Admiral tv set production lines. It is very touching to see these sets out there today being restored and put to work again.
Dan you are a good man tutoring the youth. I wish I could go back and THANK Charles E Stone in Brea, RIP. Electronics is the addiction that needs no rehab.
It needs physical space though.
@@gavincurtis and vintage electronics often smell.
@@directcurrent5751 it's (vintage electronics) most often a good smell though! :)
Disk capacitors use a ceramic dielectric, and so the capacitance decreases as the voltage increases. Since electrostatic deflection CRTs use high voltage for deflection (as opposed to high current), ceramic capacitors are a terrible idea for such an application. Metallized polypropylene film capacitors are the best choice.
I was gonna say the same, but you beat me to it 🙂This may also be the reason why the caps in Shangoo's set were butt-to-butt: as the DC-voltage-induced capacitance change made one cap loose capacity, the other would gain and both would compensate each other a bit. Even better compensation if you anti-parallel the Cs, then compensation is close to perfect.
This varying capacity with DC voltage also explains the vertical non-linearity: at the top the DC bias increased the capacity and at the bottom of the picture capacity decreased and so the lines were closer together.
I paused at 10 min in to look at comments since I was thinking this. There is a significant voltage coefficient of C vs V for ceramic caps. On modern switching power supplies, we use ceramic surface mount caps on the low voltage outputs instead of electrolytic or tantalum on a lot of designs at my company. One has to review the graphs of the C vs V carefully. These are for things like 6.3v or 10v rated caps used on 3.3v or 5v supplies. The smaller the ceramic cap package size is, the worse the reduction in C at V is. I could imagine used in a linear amplifier that could create some strange distortion.
I just posted this and then deleted after seeing your post! Vendors are finally acknowledging the problem and providing us analog designers some useful graphs. For the types we use to set the pole on LDOs you can easily lose 2/3 of the nameplate C at 50% rated DC bias. If it isn’t an NP0, it is lying to you.
Metal film resistors are laser trimmed to hit those 1% numbers. They use a spiral pattern. Buy a resistor, get a free inductor. Buy a high k ceramic cap, get a free varactor.
Would an NP0 dielectric work better? Are NP0 dielectrics available in 6 kV ratings?
That young fella is so lucky to have someone like you with your wealth of knowledge and years of experience in repairs in vintage electronics to coach him. This sort of thing is not taught in Schools but actually its a valuable gift offered by older generations, I am self taught in electronics by trial and error over the years and I really wished I had a skilled mentor when I was young, so much I don’t know and I love watching this channel!
We are all blessed to have Shango's content. I sure have learned so much and improved my confidence and motivation to do more.
Yay! Roundie, all tubes, vintage, and all around an up coming electronics technician in advanced training!
It the class of dielectric that's the issue re ceramics. The physically smaller caps with equivalent ratings have a dielectric with a high constant, but it varies with applied voltage enormously - much like a varicap diode!
Physically larger caps use lower dielectric constants material or simply lower applied field so they are much more linear..
By placing larger value capacitors in series also reduces the applied voltage and therefore the linearity.
The swapping over the caps achieves nothing; they're not polarised as per electrolytics.
I noticed in the parts list of the 19A1 chassis they only say ceramic capacitor. But in the tuner section it says things like
-750 temp. coefficient, zero temp. coefficient, or ceramic, Hi K. Apparently this is one place certain higher cost and design
of capacitors were needed. Many common ceramic capacitors back then were also about +80/-20 too. "Not all disc caps
are created equal." So true Shango. Don't forget that some resistors can also cause noise in the signal path. Just checking
the resistance isn't enough. Best advice about modern Chinesium stuff ever at 1:07:45! Awesome night vision analysis
of SMD in that IF transformer which was repaired correctly. Thank you sir for this excellent study in TV repair.
Dan love your videos. I am 75 years old and back in my youth I worked for a refrigeration and electronics repair business. My boss worked afternoons as a electrictrition. Days and weekends we were always busy repairing tvs. Ben would do the fridge work. And I got tvs. What a gotcha feeling you got when you fixed a bad cap. I never had a silver mica disease but was aware of it. Repaired lots of caps in the if cans.
I just spent almost two hours watching this video, and it was like a good book, I couln't stop watching. This brought back so many memories, like drum tuners and fine-tuning every time you changed channels. I certainly learned something about the voltage induced variation of capacitance in ceramics: never known of this and had I known, I wouldn't have thought it would have such a profound effect on vertical deflection! I have been tinkering with electronics since 1962 or so and I was impressed with your dogged determination to track down each of those unrelated faults.
Hell yeah. A movie of a repair video. I like these extended and in-depth repairs,. Thank you man.
Outstanding diagnosis......and the visual of the mica was excellent.
Stuff they don't teach you in engineering school:
As far as capacitors and high voltages, I found fhe same kind of thing out in HV PA linear HF amps. I fussed with those little blue caps forever, (and their brown cousins) until I swapped them for some old big discs from CRL. All my oscillations went away, and I could neutralize. I will measure the UHF Q and see if that's a thing.
I found metal film R's just don't work well at anything above a couple hundred volts. I battled a bunch of them in an HP181 scope for years. You gotta find some of the BIG ones for the tube stuff, or just get some carbons. I use a signal tracer with a coupling cap and listen to the B+. Hissssss! -aha! Think silver mica disease.
Speaking of silver mica disease, I've seen it appearing in just plain old dipped silver mica caps. Oxide creeps up the leads and gets inside the droplet, and it's party time. Yes, those boxy silver micas do it too. Ugh.
I also have a 6kV adjustable supply, a resistor noise bridge, and a UHF Q meter to figure some of this out. But the ear tells much, just like night termites. Dang! Those bugs are crazy!
73's. W3IHM
This video is a great demonstration of your analysis skills. All of the issues this TV had were somehow unusual and difficult ones to diagnose. Congrats, you are a master!
Tenacious is the term I would use to describe Shango's efforts on this set. Laughed a few times when his comments caught me off guard. Good stuff.
I've realized that the shells of big paper caps reach over from one point to the next and internal foil shield prevents the radiation of the signal. When you recap with little caps the long leads radiate out. Many old radios that I've recapped I've repositioned the place where the cap goes so that the lead won't be as long and it has made improvements in the signal.
I usually wouldn't sit through an almost 2 hour anything...but this was worth every minute. Congrats and bravo master shango!
shango this guy is not the only one you inspired to start working on sets, I do it as a hobby but your videos taught me a love of diagnostics which has led me to my career today doing diagnostics and repair on commercial food equipment
And tell you what it just amazes me it's the little things that you catch and that you find that the average person would have looked over or would have drove them nuts or they would have gave up on the set it's always amazing watching your videos at the wealth of knowledge anybody can get a set go and restore set go through and do complete restorations on it but your style and approach in the way you work on things is just
He tried to get most capacitors changed for solid states, but they have different properties and usually have better performance, which puts a system out of whack. More effective where the specific circuit relies on a specific ESR the paper caps had. Even a diode rectifier could go for a higher performance that a lamp would do and cause a bigger voltage/current than the tube counterpart.
Nice to start my saturday morning will coffee and Shango. Makes my morning so great. One of my favorite TV programs to watch. About the only good program to watch these days.
What you did for this set is just unbelievably fabulous 🤩.
So true
Excellent video. Love long format. Seems like if I'm fixing a car, computer or radio chiropractic adjustment to follow in every case these days.
These long form videos are my favorite. The section on the IF can and the silver mica arcing was awesome. BTW, there's a local guy who still works on older gear and is somewhat of a legend around here for fixing anything. I turned him on to your channel with one of the videos resurrecting a desert TV. He's also interested in the topic of silver mica disease so he'll definitely be watching this one.
One of the deepest diagnostic dives I’ve ever seen you do. I chased a similar problem in my Motorola VT-71 and never really resolved it. I’ll have to check the analogous can in mine. The night vision conformation was awesome!!!
I look at a lot of repair videos and restoration videos on many channels. This channel is the best by far from Shango. His videos very informative very interesting and entertaining. His EOL videos of the best on CZcams, thank you for such great entertainment
Well, I sure enjoyed this almost 2 hour long video and learned a bunch as well. I had a Motorola like that in 81, got it working pretty well. Even found a NOS CRT for it in an old TV shop in a seedy part of LA. Good times.... I was 17 at the time, and was already picking up TV's off the street and learning to fix them. Let's just say my Parent's house had a TV in absolutely every room!! 😁
This 4,7 nF x 6 KV ceramic disc costs about 40 to 50 bucks each one here in Brazil. The film capacitor with this same value and WV costs about 5 to 10 bucks.
Greetings from Baltimore, I am always impressed with your troubleshooting skills, and your hilarious comments and political viewpoints give us all hope for California yet. 😎
When I was Much younger in My House they have 12 inch or something like that Black and White Admiral TV It had The Instant On Feature Love it back in the Day 😁😁
Nice to see a younger generation enjoy vintage electronics and using a slobbering iron properly. Good looking work! I really enjoy that you put these older roundie tv's on here. These are some of my favorite videos that you put on here. For what it's worth, when I replace rectal fryers such as 5R4's and 5U4's with diode such as 1n4007's, I put a 250 ohm 10 watt wire wound resistor in series with them and it closely replicates the voltage drop of a tube. I like to keep things original as much as possible though.
Rin Voke 'I don't understand' or rheumatoid arthritis or shangism. I do love these long form deep dive videos....cheers RIP Calculon
That makes a lot of sense with disc capacitors. They fluctuate capacitance with temperature.
Yes with temperature but the problem here is the disc caps change capacitance value with applied DC voltage. In other words not good for this application. OK for decoupling caps, noise filtering etc... but not for preservation of signal shape in a circuit like this.
This critical choosing of capacitors is exactly the reason why Dumble faired so well with his bespoke amps.
Always look forward to the entertainment....
When on the rare occasion I can find a moment to tune in to your channel
go shango.
Cool! Almost 2 hours! Just started watching.
Very informative video , I learned a lot of valuable information as fixing these old sets is one of my hobbies . thanks
My cat likes your voice he listens and naps
Hey Shango, there is no reason to apologize for anything concerning this video! One helluva job bringing this thing back to where it got a decent picture. Good job!
Thank you for expanding my english vocabulary!
This was the longest video I've seen so far. There is no doubt that you deserve a Ph.D. Despite my broken English I was able to understand a lot.
Hello from Israel
Thank you for showing us how to fix this CRT Tv's. Thank you for teaching us what to use and need to use correctly
Nice video with some hard problems to find. Good work Shango!
Extra long video from El Shango...great treat for a weekend!
What great diagnostics of the silver mica problem!
sweeet ...so many lessons in this vid, both technical, philosophical
beautiful set!
I restored one about 5 years ago, Yes use paper caps in deflection circuits! No issues yet with 1 st IF can and mine has a hot 7JP4!
A nearly 2-hour video on a nice looking TV? Sign me up!
A long excrutiating trail of fault-finding!
For a less-than stellar reward.
A historic first... video-expressed SMD!
A break for violently, audibly munching termites!
Also featuring bad solder joints, a mis-wired repair, and inappropriate replacement parts!
Exhaustive! Shango is in top form here.
Thanks for a silver Mica disease demonstration. I certainly will remember that.
An almost 2 hour long repair video... what a great way to end the day! Thank you for all your effort in sharing all of this with us.
I found your channel very happy because I joined in learning
Yikes.. that was s tough one. Dang, so we gotta watch for SMD on TV cans now? Noted. Thanks for doing the setup to demo the SMD with the night vision. That was awesome! Mr Carlson recently did a video on chasing down noisy components with his super probe, then verifying with a regular signal tracer using the "noise" function. I knew it sent B+ out across the terminals, but didn't quite understand how that function worked. He found a noisey silver mica of all things. And it was intermittent at that.. but at the noise level he was searching at, he was able to locate it. That super probe is stupid sensitive. Great video sir! 👍
That's crazy!! Never have I heard termites make that noise!! Pretty cool stuff.
You did a fantastic job on that TV Shango. 👍
RIP Calculon....Squeak !
The small screen set B/W TV was a status quote for people who can effort it back in 1950-1960. It was very expensive like $250.00 a set back then that equivalent to $6,000.00 during these day base on gold standard that about $37.00 an ounce back then. I used to work at what used to be a Raytheon Power Tube division that manufactured Dumount TV Plants back in 1983-1993 and I have catalog of these old small set.
Well done for getting that to work as well as you did!
It has an imperfect but usable sort of look to it.
People in Britain would sometimes try to cobble together a T.V. Set around a surplus Radar Tube in the 405 Lines era.
I wonder if there is anyone still alive who remembers Dr Flack's Viewmaster?
Waited a while to see you do an electrostatic set! I’ve got a halicrafters set in this style that I can’t for the life of me figure out why the horizontal won’t deflect fully. Hopefully you can do some more of these soon they’re really cool sets!
The helicrafters are very touchy with the main high voltage cap. The helicrasfters with that tesla coil looking high voltage coil i had to try a few diffrent caps befor i got mine to behave.
Great Work, I also used these blue capacitors in my GBR Tube-radio they also caused some major problems...
I never knew there were electrostatic-swept TVs but I guess it stands to reason, given where the CRT came from and how it had been used, before Genrad divied up the patent rights to RCA and DuMont. I've poked at quite a few radios and amplifiers over the years, but not one TV set, except to canibalize - not repair - a few for interesting parts when I was a budding young mad scientist. And I built an ES-swept Heathkit o-scope as a teen as well. That introduced me to all the concepts dealing with the CRT; amplifiers, sweep circuitry, retrace blanking, focusing circuits, and so on. But every TV I ever touched had a yoke.
Very enjoyable & interesting video, thank you!
I had no idea it was actually possible to hear termites doing their thing! Wow.
(Yes, I watched the whole video. That TV really made you work for it. The singer toward the end was Ronnie Milsap.)
Killer info here, glad i found this channel,
nice job on those 7" sets. very educational
You are very self-aware.
Hello Lord, that was the one home dinner. I took you forever, I would have sittin had 10 coffee breaks trying to figure that 1 out. I never knew that you get market disease in the cans and TV. I've never seen it. I've never heard on it for years and get back into it again. Getting old, nothing to do. But you wish this year before you left Pete out. Maybe to try and figure something like this up. Do you do the fantastic outstanding job? I watch you all the time names. Danny. I don't say too much. I just watched all your videos. But you do a fantastic job, and you're all right? You're gonna be proud yourself. Held. Pay a patch yourself on your banks. So you just have a good job, but you take care. Watch out for everything and just have a very super swell day.🎉🎉😢
WTH?
I really enjoyed the video on the Admiral. Looking forward to seeing the resurrection of the unmolested one.
I enjoyed every minute , ty
EPIC video ! thanks ! the editing must be hell on this one !
Pretty interesting one I enoyed the video and the fixes thanks
As a kid I had a few 7 inch sets but they were all transformer less series sets. Tube lineups such as 12SN7 or L7s and 25L6s.
Thanks.
1:48:57 Look at that.. Our minds are perfectly capable of filling in between the lines, so to speak, all 480 of them!
Now this may sound strange, but when I'm watching 480p, I feel my mind working subconsciously, filling in the "missing" info. When I'm watching standard(720) HD or up, more of the visual info is being spoon-fed to me. And while it's a sharper, subjectively more realistic TV picture, it feels like I didn't accomplish anything by watching it.
Thanks for the video.....and KEEP COMING.....
very interesting video, very exciting !! Very good work as always. I think, the noisy "fuzzy" h-sync is caused by the filter-capacitor in the h-sync-DC-PLL/AFC-Voltage (time-constant too low). - - - The WIMA FKP1 are optimized for high impulse-load in a inductiv H-circuit, maybe they are not optimal working in this static-circuits with low current but HV. Keramic-Cs in the range of nF have complete other dielectricum in comparison to ceramic-Cs in the pF-Range (low pf value up to 200...300pF: much better and stabler). Maybe the nF-ceramic-Cs are too much voltage depending... this capacitors are really crappy and only unsable für blocking or filtering, not coupling or time-relevant circuits
...and here is a Bob Andersen-Video with the same mica-problems in Audio-Filters of an admiral: czcams.com/video/CJyZZYkci78/video.html ...found coincidentally because your hint to this chanel
Some ceramic capacitors have a capacitance that is dependent on the voltage across the capacitor. Just like a varactor diode. Thats the nonlinearity you are seeing in effect. Thats also why they have such a wide tolerance. They are only for decoupling where the exact capacitance value does not matter.
Thank you for that video, i can´t wait for the Resurrection 🙂
Will be looking forward to you firing up the "virgin" chassis shown at the end of the video with the shorted B+. What I have learned here (after many years at the workbench) is that a particular capacitor is not necessarily the same value at varying voltages. So I'll be interested to see if the wax tubulars in the "coming attraction" are (first) any good at all, and (second) if the top linearity winds up being better than with the caps used in the two featured sets. Several super videos recently. The AM stereo for sure, this one, and the prop rental house.
Beautiful Admiral 😍
Todos os seus vídeos são top, parabéns irmão, Deus o abençoe.
Termites! Im glad we don't have them here. Great shango video today.
Excellent video!
i have this old school book, electricity projects. 1950 shows how make your own ear phone, your own telegraph lines, own radio out of pretty much 1900 style home made parts Need the book when we go back to the dark ages again and the electricity gets cut off , there be big panic if the electricity gets cut off.
I just turn up the bench power supply to 32 volts, (which is as high as it will go), and put that on the caps for an hour or so with those old rectifier tube parallel filament sets and radios. (pull out the rectifier tube) It's better than nothing and detects one that is hopelessly shorted. 32 volts is not going to damage anything. I've gotten good results that way and even at 32 volts you can watch the current draw go down.
That arching was neeto to see, thanks!
I've got one of those vintage TVs that I last powered up about 55 years ago; it gave a raster! As the main PS selenium rectifier stack started heating up, I pulled the plug. At the time, I did know about bad filter capacitors... The knobs were carefully boxed up and subsequently lost... Today's challenge would be to design mods to give it an HDMI input since the CRT deflection can handle much higher frequency than NTSC; why not? LOL, I need to get rid of it by finding it a good home....
Even though I have absolutely no experience with tube based electronic stuff, this seems like it'd be fun to do, to work and restore these old tvs.
Brilliant Sir so interesting
I could rent movies and get zero knowledge. These videos have taught me to diagnose before throwing the parts cannon at them. Even though parts are cheap for the most part it adds up.
Ronnie Milsap .. those videos go back a long way, as in the 80s.
Shango that baseball game looks like it's receiving an offset of 20 khz back in the analog days. The 0 khz, 10 khz and 20 khz offsets helped with identifying co-channel interference back in the analog days.
New Jane Birkin bag at 1:38:53 Great diagnostic on that IF can. SMD lives on...............
VERY interesting to see the effects of the capacitance variation in regards to voltage on some of those ceramic disks👍 When you first pointed out the jitters on the video signal, I jokingly thought whether this was maybe silver mica disease on a screen, and it really turned out to be so😆 May it have been possible to attempt putting a pretty large capacitance foil cap in line with the shorting mica cap outside of the IF can on pin 4? Excellent video!!
What a great way to start my day! A very nicely done video with great views. I've always wanted one of these roundies I'll be keeping an eye out for one. When you were doing the last IF alignment was the tube next to the antenna lead arcing inside or was it just reflecting light? Also what kind of signal generator is that? That looks to be a handy tool to have. Thanks Ted
Almost looks like that the capacity depends on the voltage across. It's a property of ceramic dielectrica. Static deflection is by definition linear. I would have a look at the deflection waveforms on the plates.
Bob Anderson talked about this many years ago, he noted that the value of disk capacitors changes with voltage and should never be used here!
Watched this video 3 TIMES..... Each time caught something more to think about.
Tech's from the past did not have to deal with the difficult problems like this.
You could just buy the capacitors that you needed and the set was fixed ! Not to mention Silver Mica IF problems !
These are EXCELLENT Videos for the beginner as well as many of us old timers.
The future may involve alignment of the rinvoq coil to achive the proper decollette level.
Thanks Buddy for yet another great video !
WRONG !
The ceramic disks could have a large voltage coefficient (capacitance changes with voltage) which might affect the linearity.
exactly this. been yelling this at the screen for the last ten minutes but shango didn't hear. chonky thick caps often have non linearity with voltage
I'm a fan of the change one and test again
High K ceramic capacitors have a non-linear capacitance vs. applied DC voltage. IMSAI Guy did a video on this recently when he had a 555 timer module that used disc capacitors for the timing and it didn't work right. Replacing them with film totally solved the problem.
綺麗なので驚きました。とても素晴らしいでしょう。👍