What happened at 33 minutes is nothing short of amazing. HDD magnets and a resistor, some WD 40 and 90 years is just giving the finger to newer stuff. I love this channel!
Yeah!!! 2 fingers to the throw away garbage they make now. The quality of everything has gone down hill. You don't use things 20 or 30 years anymore. Your lucky if anything last a few years now or gives you good service. Shame really...
You know, the 1930's is when the basics of modern society really fell into place. Radios became common in the 1930's. As did telephones, and electric lighting. Cars changed dramatically. 1920's cars resemble horseless carriages. You don't get into a Model T, you get on it, like a tractor. The 1930's had cars with enclosed cabins. And televisions existed by the end of the 1930's, as did movies with sound and color. All of these were primitive versions of what we still use to this day. And this all happened in spite of the Great Depression, and in spite of the Dust Bowl.
Shango is a bit of a grandmaster of what I would call "freestyle repair" where he takes "calculated" risks and uses a lot of tricks of the trade he must have gathered in his long career... Most of them work too :) Hats off for his repair of this old-timer on the cheap but effective !
Allied radio in Chicago sold kits under the house brand of knight-kits. They were headquartered in Chicago. I spent many happy hours in the store as a child many many years ago - so, yes, your signal generator and that radio are "related". Nice video. Lots of fun!
Your videos make it fun. I feel the same way about amateur radio. I am 71 years old and it is a great hobby foe me. I have no formal background in electronics but have learned from books and people like you that share their knowledge. After watching your videos I decided to to try repair a EICO 715. It is just an old piece of test equipment my dad and I used back in the 1970's when we were into CB radio. Wow did I open a can of worms. I had to find replacements for 1N56 germanium diodes. I did get all the functions working except for the modulation testing. I will go back to that at some point to see if I can figure that out. The worst part to working on it is that it is hand wired and stacked selector switches are used. Now I have great appreciation for the patience you have. Thanks for your videos.
That will be a nice looking radio when it's refinished, it reminds me of my first radio restoration, it was around 1983 and was a 1938 Silvertone mantle radio. The inside of the radio was intact with all the tubes, but in those days, I knew nothing about how to get schematics, later finding out that every library had Riders manuals. I persevered looking at the tiny and faded schematic inside the cabinet. The field coil was blown, so not knowing the resistor trick, I completely unwound the field coil and removed the shorted section and rewound it with the remaining good wire. It took a long time but it paid off and that radio works to this day. It would be a much easier operation for me today because I have a bobbin winder, which would probably turn a job that took many hours to a couple of hours.
How beautifully simple were electronics back in the days... I have a 50s bulgarian radio from my grandparents which have permanent magnet speaker and a separate choke for the plate voltage LC filter.
Even more depressing than Soros buying 40% of these radio stations is the fact that his younger son is now in place to run the company. He is much more committed and has a lot more energy.
dave tipton had a speaker with a bad field coil and he managed to rewind it. he posted a video in the last few months doing it. it did look like a lot of trouble though, he used a chinese coil winding machine to do it.
The stolen radio tower is a little less than 2 hours from me. The thing about the original news story that made me suspicious was that the tower had been supposedly gone without anyone knowing it, implying the station either wasn't operating or if it was, had no listeners that cared to call the station to report that it was off the air.
similiar thinking here....how do you take down a functional commercial transmitter and nobody notices?....it was a live station and the transmitter and antenna disappear, hunh?
This Knight radio (model 98AE-184K) is the same as a Sentinel 98AE. The metal top-hat shaped bias cell can be replaced by a 1.5V watch battery with the negative side towards the output tube OR by a 4.7 to 6 Megohm resistor with a parallel .01uF capacitor across it. The original electrolytics were 8uF each so I wouldn't go over 16uF on them. Like your attack approach to individual leaky paper caps. It's why they must be all replaced. Even old tubes are cheap, if you need a new one and usually tested by most sellers with a good tube tester. They often brag about it for your decision making to buy it or not. 45 cents back then for a tube is worth $10 today, so you are doing good. Too bad the 6G5 eyetube was so weak but there is a 1Meg resistor in the tube socket that can go really high in value and cause dimming even in a newer replacement tube. Your tips at the end are very much appreciated Shango. Great video! Steve from IL
Hey Shango066, I just wanted to say having gotten addicted to watching your videos this winter I finally got inspired to get back to tinkering with electronics. Last night I resurrected a little Emerson 547A with a case cracked all to hell that was left for dead in a late friend's basement. A few capacitors and tracing a shorted wire (one tiny strand from B+ to the pilot light), a quick alignment and it was alive and well in two hours. Thank you for (indirectly) saving this radio!
If you believe for one second that modern mechanical hard drives are more reliable than the old ones I got some bridges I'd like to offer you!!!!! I've worked in the industry for decades and they have gotten less and less reliable over time. Also, you can open these and they will still work, but you have to torque them down to the right specs or they will never work again. When I was college, I had a class that had a hard disk with a transparent case. The problem is if you don't use a clean room, it is near impossible to keep particles out of the case when you open it.
Mallory bias cell. You can put any one and a half volt small coin size battery in its place. Or if your adventurous there are ways to rejuvenate the cell by drilling a small hole in the side adding some liquid and sealing it. It is a cell that produces almost no current and the circuit demands almost no current. They got away from those in one or two years. Went to self-bias.
I keep hoping you'll attempt to repair the field coil. I would try. After all, it's put together with screws. Just unscrew it and look at it. The open area might be clearly visible and fixable. Or maybe not. But I've been happily surprised many times.
My dad fixed a Philco 20 by repairing an open field coil. The break was conveniently on the outside winding of the coil. That radio played for years after.
I really enjoyed watching that . What a lovely old radio .I would enjoy restoring the cabinet finish. Sir you have the best channel on you tube !! Best wishes from the UK .
I've only worked on transistor radios for years and only just started watching your tube radio videos and I have to say they are fascinating to watch! My eyes are not what they used to be and you great camera work and closeups make it easier to follow along than if I was there in person watching! Thank you for your hard work!!
I always wonder about magnetization of the pole piece. Were they originally magnetized? Surely it may happen over time. I also understand that these electromagnetic speakers can be damaged by reversing the polarity of the field coil. Seems odd, but that's what I've been told.
Oh my favorite kind of radio! AM/SW tube set. I do like that dial string assembly where it just comes off as a unit and you can repair it on the bench. Looking forward to updates on this one. I live about 30 miles from the radio tower that " was stolen". Lol. That place has been off the air for years on AM. Another great video. Might get me motavated to work on one of mine. Thanks!
That came out quite nicely, especially considering the fact that you had to guess at the IF frequency. I would replace the speaker with a vintage PM one that has roughly 3.2 ohms impedance, that's what these old sets like. I built a little box a while back that I use with all of my vintage radios/phonos. Basically it's a wall outlet box that has a light switch, and outlet, and a 1 amp slo-blo fuse. And yes, j-hook for the win---I just don't see the point in stressing the lugs on old tube sockets
Those were kits, you could buy them from Allied Radio. My neighbor gave me a bunch of their books when I was a kid bc I loved to look through them, hoping one day to build my own. These days I can say I have done that and thank my neighbor who is no longer with us. He was my Mentor.
These radio repair videos are really good. Lots of learning and great tips, I try to watch it whenever I have time. It's fascinating how you can experiment to improve results. Congratulations!
If you could get a couple big donut magnets like RadioShack used to sell you might be able to carefully take apart the speaker and replace the field coil with them, but it will be tricky to get it aligned so the voice coil doesnt rub.
Thank you friend! As always, great aesthetic pleasure was received from viewing another masterpiece. Special thanks for using the blue pencil. This is my favorite color!
You can use the primary of almost any power transformer (secondary disconnected) as a choke. Also, HDD magnets are usually hexapolar - looking at the arc, along the top are NSN, and along the bottom are SNS. So when that type of magnet is attached to a ferrous metal, each of the polar pairs is pulling against its opposite neighbor through the base metal.
@@janosnagyj.9540Swinging chokes have air gaps, and yes their function is more effective than a 'regular' choke, especially when dynamic changes in the load are expected. But outside of a few specialty applications, 'ordinary' iron-core chokes were used. In this application, the difference would be negligible.
Thanks for showing harvesting the magnets from the hard drive. Very timely as I was going to trash an old one. Now I have magnets to show my grandsons!
About those 30s eye tubes, they were only meant to last about 1200 hours (later as the tech advanced they were making 6E5s in the 70s that were closer to 1800 hours- those have a glow that looks more blue-ish in hue). 1200 hours is about 3-4 years of use if the radio was going to played about 1 hour per-day after the original purchase. The 6U5/6G5 and 6E5 are "for all practical purposes" interchangeable in most applications. But the 6E5 moves faster with the same trigger, and on really strong stations may overlap itself in the closed position. If you can live with seeing that happen when tuning into local 50 kw flamethrowers, there's no harm in using the more common 6E5. Now the soviet 6E5 is electronically the same as the American 6E5, but it uses a different base so the substitute for those requires making an adapter. Btw you can tell this isn't a Philco because it has an eye tube. Philco hated RCA's control over radio patents in the 1930s, and intentionally refused to ever use eye tubes as a form of petty-revenge (instead their high end sets got shadow meters). Philco & Zenith also tried, for as long as they could get away with, to force consumers to use G & GT tube types because metal tubes were an RCA innovation. They employed all kinds of tactics to discourage using metal tubes... like having tube shields that slide onto rivetted-on receptacles shaped so metal tubes can't fit through them to plug into the socket, or not grounding pin1 (needed for the metal types' shields) etc.
@@jdmccorful That can be an advantage, it might be the perfect size to replace the coil with them, if you stuck like 6 or 8 magnetron magnets on top of each other.
@@jdmccorful I don't think they would be heavier, it is probably lighter because most of the coil is copper, which is very heavy. It looks to me if you remove those two screws, the bracket falls apart and you can remove the coil and install the magnets. If there's a gap, just wedge a sheet of steel in it. But one important thing (apart from the matching size) is the direction of the magnetism. I don't know if magnetron magnets are magnetized as the two flat surfaces are the two poles, or one half circle is one pole and the other half circle is the other pole. You need the two flat surfaces as the two poles, as that's what matches with the field the coil makes.
Well Done Shango really enjoyed the use of a 6AQ5 sub never knew that working on a philco 38 model with same tube you had but just AM band I will use my learning knowledge I got from you thanks for showing. Love Saturday Morning coffee with Shango
That's a interesting radio! A classic. Very cool to see the older components. They don't make 'em like that anymore. And the key word, SERVICEABLE! Awesome video! 🍻
@26:30 - If anyone cares, you can soak the magnet assemblies in acetone overnight and in the morning, carefully pry/slide the magnets off the brackets. They bite your fingers a lot harder when the brackets are gone. You have been warned.
Ah, I wondered how that glue could come off. I pried a bunch of but it's hit or miss if you break the magnet or peel off the nickel / whatever coating is on the outside.
One thing you don't need to concern yourself with is being accused of appearing "Presidental" . Especially with the standards we are seeing right now oh "blue gloved" devil. Great common sense and great video! Thanks for your endeavors!
Never heard of a gimmick capacitor before. Looked it up. Its a real thing. Love learning new things like this. Sorry to hear Sauron is taking over a lot of your radio stations. I can't see anything but bad coming from that. He's not a good person.
Shango, I watch most of your videos but never post a comment. I totally agree about what you said about the old man from Hungary. I have made similar comments about him and other similar behavior about the destruction of the core of this nation, and I got an immediate warning about my "comments".
When I worked in a radio repair shop in the 80's, the one thing I could never do is replace the dial string. I left that for Walter to do. (He owned the place.)
My guess would be that if he doesn't shut it all down, he'll add the stations to his propaganda machine to an even greater degree than they've already declined into.
@volvo09 Oh, he will. He passed the torch to his 38-year-old son. He’s just as bad or worse. His son is currently dating Huma Abedin-Hilary Clinton’s girlfriend and Anthony Weiner’s ex wife.
This country is done for anyway. Stop worrying about it. All empires fall eventually. Do you want a good radio station? Do what I did when I wanted a good TV station: make your own. A raspberry pi can do this with ease.
When I was a young soldier, in the old "black boot" Army, we used to use old diapers, you know the real cloth type before pampers came along, to spit shin our combat boots. In the Army back then everyone above the rank of SP-4 or Corporal was very interested on how well you spit shined those old combat boots. Now days I still. Use KIWI on my black loafers but just for brush shine, it keeps the leather supple, looks good and brings back those memories of when I was a lolley SP-4 before I got my Stripes and got to stop doing grunt work,
neo magnet on the back of the old speaker works great. modern headphone speakers like 20-40mm usually have the rare earth in them. they are usually glued on the back so just knock them off with a hammer
Imagine, a 10 year old experienced Abraham Lincolns assassinated in 1865, then at 80 could have listened to this radio, and traveled by airplane, and automobile. Wow, seeing a complete change in technology in thier lifetime.
Appreciate the final minutes of this on technique. A while back I showed some experimentation on the bias cell with a variable buck converter and did not get a lot of difference with the voltage 1.5~3.5 V. I think a coin cell would work fine and will be my eventual solution on my '37 Grunow which has one. Thanks for another interesting video.
I did a bias cell bypass on a Stromberg by disconnecting the bias cell entirely & hooking the middle lug of the vol control straight into the 6F5 grid, then disconnecting the cathode from ground and putting a 3.3uf cap in parallel to a 1500 ohm resistor. Been working great for years and plenty of volume and fidelity.
@@sgath92 Interesting. When I did a final checkout on the Grunow, I even had the bias cell completely disconnected and it sounded just fine. That may vary with a different circuit - IDK.
Hi, Great videos love the snark. On the tuning eye, you'll find a 1 meg resistor in the socket which will be nearly open. Replace that or just put straight B+ on it. It will help. Thanks!
That thing that looks like a small metal top hat is a 1.5 volt bias cell. In direct-heater tubes or before they developed negative grid bias from cathode current bias cells were used to keep the grid slightly negative. There is almost no current drain and I bet it still tests a little voltage.
So many people have no clue. Pure evil going on in this world, soon we'll have to confront reality. Love the radio repair vids, I've been collectingntube radios & need to get them all going also.
Thanks for another great video! This chassis looks like my 1938 vintage Stewart Warner R1915-D, except that it has no shortwave, no tuning eye and mine was a battery radio because it has a vibrator. The layout is VERY similar otherwise right down to the 41 tube. I found mine in an old farmhouse junk pile I’ve got a 6U5 eye tube that also says 6G5 on it. The 6E5 has the same socket and uses the same tests on my tube tester. I’m not sure the difference except for the 6E5 being a half inch shorter. You might be able to substitute one for the other.
Keep up the good common-sense repair videos. I try to second-guess each step of your troubleshooting. Also keep buying parts from our friend Bill M. in Sunbury, PA. 24 years ago I sold him my Admiral TV that is on his TV parts page.
Would really like to see another one of those desert find tv ressurection vids. The ones where they look completely baked / beyond repair and you somehow manage to breathe life back into them .
Nice pre-octal set! The RestoreOldRadios channel did a full restoration of an identical set about a year ago. The bias cell is used to bias the grid of the 75 duodiode-triode tube, just in series with the volume control; they could have used a cathode resistor instead as the diode sections are not used (the detector uses a separate diode-connected 76 triode - 1:17:00).
The schematic is on Nostalgia Air (Sentinel 98AE), IF appears to be 465kHz. 41 is electrically identical to 6K6 octal. I'd try also a good speaker, the magnets may not be doing a good job there (magnetic field shunted via the armature?)
They could also have used a 5 to 10 meg ohm resistor and a capacitor in series with volume control, on the grid of the 75 tube and had grid leak bias. Inserting a cathode biasing resistor would up set the diode AM detector function.
@@JCWise-sf9ww True, but note that the detector uses a separate 76 tube, so the bias resistor at the cathode of the 75 would not upset anything. One could argue that a single cathode bias resistor would cost less than a capacitor and resistor for grid leak bias, but then again they used an extra tube and a bias cell (!), so cost was not the issue.
It would, but that's desirable in this circumstance - the speaker has two coils, one with many windings used as the choke, and another with only a few windings to move the cone with audio. The effect is minimal, because of the soft iron core.
I guess you could experiment substituting that field coil by a coil out of a contactor, an old school relay that could be disassembled, or a solenoid from an irrigation valve. Just find one that fits in there and see what happens.
Seeing the weak #41 and the substitution of the 6AQ5 reminded me of the #89 tube, which is very close to the #41, but the grids are wired out to individual pins rather than having G3 tied to the cathode internally. One of these days I'll try it and see what happens. The #89 had some military application and seems to be a whole bunch of them around, but I have found very very few radios that use one. The #41 & #42 became the 6K6 and 6F6 respectively.
Never seen one of those Mallory cells on a uk radio, and I have a huge collection of sets from the 30's, I suppose they never made it across the pond. You need alot of patience to rewind a field coil, well done using neo magnets, I'd never have thought of it.
21:13 Sticking the magnet on the back will not give magnet field close to original sensitivity. The efficient fix is to take off the field coil magnet bracket, put a round flat neodymium magnet on the edge of the core and secure it with glue. The next step is to put the bracket back, but with couple of steel washers and longer screws. If the neodymium magnet did not fall off the core during this process, the speaker should work and look almost original.
Yes the big SCSI drive magnets take me back! WAY back when I used Apple computers more seriously I had a 'Mac II fx' connected to 5 of those giant scsi drives I got at a tech surplus flea market for next to nothing. VERY fast and cheap for the time!! Not that I expected much of that setup with an 030 processor, lol And of course they didn't last long after being used! The head amps failed one by one. Now I just have the crazy-powerful magnets and a spindle completely filled with just platters, no space in between.
What happened at 33 minutes is nothing short of amazing. HDD magnets and a resistor, some WD 40 and 90 years is just giving the finger to newer stuff. I love this channel!
Yeah!!! 2 fingers to the throw away garbage they make now.
The quality of everything has gone down hill. You don't use
things 20 or 30 years anymore. Your lucky if anything last a
few years now or gives you good service. Shame really...
LOL!@@bigalsmallengines
"Ice cream and diapers... sounds Presidential." 😂
It’s so cool when you start hearing sound coming out of these old radios for the first time in many years!
Dial strings are really fun - they make you humble and test your mechanical ability
'fun' ..hmm, yeah, especially many philips drives,
I did my first one last year. It went mostly well, luckily the old sting was still mostly strung. My job works but there is a tiny bit of play in it.
I’ve done a few in the past…😊
No 90 year old radio was harmed in this video LOL great job Mr Shango hour long videos are great
You know, the 1930's is when the basics of modern society really fell into place.
Radios became common in the 1930's. As did telephones, and electric lighting. Cars changed dramatically. 1920's cars resemble horseless carriages. You don't get into a Model T, you get on it, like a tractor. The 1930's had cars with enclosed cabins. And televisions existed by the end of the 1930's, as did movies with sound and color. All of these were primitive versions of what we still use to this day.
And this all happened in spite of the Great Depression, and in spite of the Dust Bowl.
Shango is a bit of a grandmaster of what I would call "freestyle repair" where he takes "calculated" risks and uses a lot of tricks of the trade he must have gathered in his long career... Most of them work too :) Hats off for his repair of this old-timer on the cheap but effective !
Allied radio in Chicago sold kits under the house brand of knight-kits. They were headquartered in Chicago. I spent many happy hours in the store as a child many many years ago - so, yes, your signal generator and that radio are "related". Nice video. Lots of fun!
"Working shelf queen" I made it! My RCA is a non-working shelf queen, the case, glass and knobs are very nice.
Peace!
"Everybody loves doing dial cords". You cracked me up. I'd rather do a Silver Mica Disease repair than a dial cord.
Your videos make it fun. I feel the same way about amateur radio. I am 71 years old and it is a great hobby foe me. I have no formal background in electronics but have learned from books and people like you that share their knowledge. After watching your videos I decided to to try repair a EICO 715. It is just an old piece of test equipment my dad and I used back in the 1970's when we were into CB radio. Wow did I open a can of worms. I had to find replacements for 1N56 germanium diodes. I did get all the functions working except for the modulation testing. I will go back to that at some point to see if I can figure that out. The worst part to working on it is that it is hand wired and stacked selector switches are used. Now I have great appreciation for the patience you have. Thanks for your videos.
You can always tell people that actually UNDERSTAND how something works because they can improvise when making repairs or even improving it.
That will be a nice looking radio when it's refinished, it reminds me of my first radio restoration, it was around 1983 and was a 1938 Silvertone mantle radio. The inside of the radio was intact with all the tubes, but in those days, I knew nothing about how to get schematics, later finding out that every library had Riders manuals. I persevered looking at the tiny and faded schematic inside the cabinet. The field coil was blown, so not knowing the resistor trick, I completely unwound the field coil and removed the shorted section and rewound it with the remaining good wire. It took a long time but it paid off and that radio works to this day. It would be a much easier operation for me today because I have a bobbin winder, which would probably turn a job that took many hours to a couple of hours.
How beautifully simple were electronics back in the days... I have a 50s bulgarian radio from my grandparents which have permanent magnet speaker and a separate choke for the plate voltage LC filter.
Dial string replacement.. the most hated repair of them all.
That radio deserves a FULL resto eventually. Amazing Shango-ONLY speaker repair!❤
He does a power up as a basic diagnosis. Shango066 knows the capacitors are, this is just a demonstration video. He may do a part 2 though.
Even more depressing than Soros buying 40% of these radio stations is the fact that his younger son is now in place to run the company. He is much more committed and has a lot more energy.
They just need to go away
Wow, the radio repair episodes are some of my favorite shabbat edutainment content. Todah!
dave tipton had a speaker with a bad field coil and he managed to rewind it. he posted a video in the last few months doing it. it did look like a lot of trouble though, he used a chinese coil winding machine to do it.
The stolen radio tower is a little less than 2 hours from me. The thing about the original news story that made me suspicious was that the tower had been supposedly gone without anyone knowing it, implying the station either wasn't operating or if it was, had no listeners that cared to call the station to report that it was off the air.
So what’s the story then? I didn’t quite follow
similiar thinking here....how do you take down a functional commercial transmitter and nobody notices?....it was a live station and the transmitter and antenna disappear, hunh?
Thank you, I have watched every video for about 5 years now. You deserve many awards.
That smoke looks like WD-40 heated to just under ignition.Cool! Only on Shango,along with the great tuning noises. Bravo!
Totally with you on the Souros thing. Yes, I spelled it wrong. He's something out of Star Wars.
Yeah, like the executive producer. What else were you thinking?
Have you seen Klaus Schwab in his darth vader space uniform? That’s Star Wars as well.
@@gavincurtis Maybe Klaus Schwab is bring down Western Civilization with his wokeness
@@gavincurtis no
I wish the old coot would croke and somehow his money going to far left organizations would get mishandled.
This Knight radio (model 98AE-184K) is the same as a Sentinel 98AE. The metal top-hat shaped bias cell can be replaced
by a 1.5V watch battery with the negative side towards the output tube OR by a 4.7 to 6 Megohm resistor with a parallel
.01uF capacitor across it. The original electrolytics were 8uF each so I wouldn't go over 16uF on them. Like your attack approach to individual leaky paper caps. It's why they must be all replaced. Even old tubes are cheap, if you need a new
one and usually tested by most sellers with a good tube tester. They often brag about it for your decision making to buy it
or not. 45 cents back then for a tube is worth $10 today, so you are doing good. Too bad the 6G5 eyetube was so weak but
there is a 1Meg resistor in the tube socket that can go really high in value and cause dimming even in a newer replacement tube. Your tips at the end are very much appreciated Shango. Great video! Steve from IL
I always look for your comments as they are usually interesting and informative.
@@johnnytacokleinschmidt515 Thanks!
Nicer looking radio than most. Always enjoy your comments.
Yeah bet when those were new they were really nice looking radios
I've never seen smoke come out of a wafer switch before. It was quite beautiful.
Definetly a Camel. Smooth.
@@billdegener8105 LOL.
i've had one spark and almost catch fire !
Like one of those incense waterfalls!
@@agostinodibella9939 Yeah.
Hey Shango066, I just wanted to say having gotten addicted to watching your videos this winter I finally got inspired to get back to tinkering with electronics. Last night I resurrected a little Emerson 547A with a case cracked all to hell that was left for dead in a late friend's basement. A few capacitors and tracing a shorted wire (one tiny strand from B+ to the pilot light), a quick alignment and it was alive and well in two hours. Thank you for (indirectly) saving this radio!
That one piece you can't figure out is a little Bias Cell. The radio case looks like philco😮
That's what I was thinking.
Were those a mercury battery?
If you believe for one second that modern mechanical hard drives are more reliable than the old ones I got some bridges I'd like to offer you!!!!! I've worked in the industry for decades and they have gotten less and less reliable over time.
Also, you can open these and they will still work, but you have to torque them down to the right specs or they will never work again. When I was college, I had a class that had a hard disk with a transparent case. The problem is if you don't use a clean room, it is near impossible to keep particles out of the case when you open it.
"they just didn't know how to build junk back then" ❤ 100%!
Mallory bias cell. You can put any one and a half volt small coin size battery in its place. Or if your adventurous there are ways to rejuvenate the cell by drilling a small hole in the side adding some liquid and sealing it. It is a cell that produces almost no current and the circuit demands almost no current. They got away from those in one or two years. Went to self-bias.
It might improve the kind of weird overloading Distortion issue but at this point I think the thing works fine for my needs
I keep hoping you'll attempt to repair the field coil. I would try. After all, it's put together with screws. Just unscrew it and look at it. The open area might be clearly visible and fixable. Or maybe not. But I've been happily surprised many times.
My dad fixed a Philco 20 by repairing an open field coil. The break was conveniently on the outside winding of the coil. That radio played for years after.
I really enjoyed watching that . What a lovely old radio .I would enjoy restoring the cabinet finish.
Sir you have the best channel on you tube !! Best wishes from the UK .
The little kids collecting diapers for ice cream must absolutely be sponsored by the whitehouse. Like a junior achievement or scouting, kind of thing.
Why not,we've got a president that wears and fills diapers daily.
That eye tube was super creepy near the end... I love it!
I've only worked on transistor radios for years and only just started watching your tube radio videos and I have to say they are fascinating to watch! My eyes are not what they used to be and you great camera work and closeups make it easier to follow along than if I was there in person watching! Thank you for your hard work!!
Wow. Cool radio. Enjoyed the experimentation. I'm amazed the speaker works at all with an open field coil, let along with those magnets attached.
I always wonder about magnetization of the pole piece. Were they originally magnetized? Surely it may happen over time. I also understand that these electromagnetic speakers can be damaged by reversing the polarity of the field coil. Seems odd, but that's what I've been told.
Since some months ago i started to use the j-hook method when replacing parts. I love it! Thanks Shango!!!
Oh my favorite kind of radio! AM/SW tube set. I do like that dial string assembly where it just comes off as a unit and you can repair it on the bench. Looking forward to updates on this one. I live about 30 miles from the radio tower that " was stolen". Lol. That place has been off the air for years on AM. Another great video. Might get me motavated to work on one of mine. Thanks!
That came out quite nicely, especially considering the fact that you had to guess at the IF frequency. I would replace the speaker with a vintage PM one that has roughly 3.2 ohms impedance, that's what these old sets like. I built a little box a while back that I use with all of my vintage radios/phonos. Basically it's a wall outlet box that has a light switch, and outlet, and a 1 amp slo-blo fuse. And yes, j-hook for the win---I just don't see the point in stressing the lugs on old tube sockets
Those were kits, you could buy them from Allied Radio. My neighbor gave me a bunch of their books when I was a kid bc I loved to look through them, hoping one day to build my own. These days I can say I have done that and thank my neighbor who is no longer with us. He was my Mentor.
Soros is 5 years older than this radio. Wish a little WD, and some magnets would fix him too...
These radio repair videos are really good.
Lots of learning and great tips, I try to watch it whenever I have time. It's fascinating how you can experiment to improve results.
Congratulations!
If you could get a couple big donut magnets like RadioShack used to sell you might be able to carefully take apart the speaker and replace the field coil with them, but it will be tricky to get it aligned so the voice coil doesnt rub.
magnetic parts tray magnets might work too
Very cool radio shango. Thanks for sharing the repair with us.
Thank you friend! As always, great aesthetic pleasure was received from viewing another masterpiece. Special thanks for using the blue pencil. This is my favorite color!
i love watching all the smoke they use to make the parts escape back out. very relaxing
You can use the primary of almost any power transformer (secondary disconnected) as a choke. Also, HDD magnets are usually hexapolar - looking at the arc, along the top are NSN, and along the bottom are SNS. So when that type of magnet is attached to a ferrous metal, each of the polar pairs is pulling against its opposite neighbor through the base metal.
Wrong. Chokes have air gaps, power transformers do not. The difference in inductance and hence in functionality is night and day.
@@janosnagyj.9540Swinging chokes have air gaps, and yes their function is more effective than a 'regular' choke, especially when dynamic changes in the load are expected. But outside of a few specialty applications, 'ordinary' iron-core chokes were used. In this application, the difference would be negligible.
Thanks for showing harvesting the magnets from the hard drive. Very timely as I was going to trash an old one. Now I have magnets to show my grandsons!
About those 30s eye tubes, they were only meant to last about 1200 hours (later as the tech advanced they were making 6E5s in the 70s that were closer to 1800 hours- those have a glow that looks more blue-ish in hue). 1200 hours is about 3-4 years of use if the radio was going to played about 1 hour per-day after the original purchase. The 6U5/6G5 and 6E5 are "for all practical purposes" interchangeable in most applications. But the 6E5 moves faster with the same trigger, and on really strong stations may overlap itself in the closed position. If you can live with seeing that happen when tuning into local 50 kw flamethrowers, there's no harm in using the more common 6E5. Now the soviet 6E5 is electronically the same as the American 6E5, but it uses a different base so the substitute for those requires making an adapter. Btw you can tell this isn't a Philco because it has an eye tube. Philco hated RCA's control over radio patents in the 1930s, and intentionally refused to ever use eye tubes as a form of petty-revenge (instead their high end sets got shadow meters). Philco & Zenith also tried, for as long as they could get away with, to force consumers to use G & GT tube types because metal tubes were an RCA innovation. They employed all kinds of tactics to discourage using metal tubes... like having tube shields that slide onto rivetted-on receptacles shaped so metal tubes can't fit through them to plug into the socket, or not grounding pin1 (needed for the metal types' shields) etc.
The magnets on your microwave oven are great as well..
But, pretty large sized.
@@jdmccorful That can be an advantage, it might be the perfect size to replace the coil with them, if you stuck like 6 or 8 magnetron magnets on top of each other.
@@mrnmrn1 interesting, but weight and mounting could factor in?
@@jdmccorful I don't think they would be heavier, it is probably lighter because most of the coil is copper, which is very heavy. It looks to me if you remove those two screws, the bracket falls apart and you can remove the coil and install the magnets. If there's a gap, just wedge a sheet of steel in it.
But one important thing (apart from the matching size) is the direction of the magnetism. I don't know if magnetron magnets are magnetized as the two flat surfaces are the two poles, or one half circle is one pole and the other half circle is the other pole. You need the two flat surfaces as the two poles, as that's what matches with the field the coil makes.
@@mrnmrn1 i believe you would have to stack NSNSNS, else they would push back. Is this what you are commenting on?
Well Done Shango really enjoyed the use of a 6AQ5 sub never knew that working on a philco 38 model with same tube you had but just AM band I will use my learning knowledge I got from you thanks for showing. Love Saturday Morning coffee with Shango
That's a interesting radio! A classic. Very cool to see the
older components. They don't make 'em like that anymore.
And the key word, SERVICEABLE! Awesome video! 🍻
@26:30 - If anyone cares, you can soak the magnet assemblies in acetone overnight and in the morning, carefully pry/slide the magnets off the brackets. They bite your fingers a lot harder when the brackets are gone. You have been warned.
Ah, I wondered how that glue could come off.
I pried a bunch of but it's hit or miss if you break the magnet or peel off the nickel / whatever coating is on the outside.
Soothing Smoke. Big Thumbs Up. That was currently very Presidential.
Knight was a brand of Allied. That chassis is very similar to the Allied B10560 from 1942 Riders - Page 12-7.
yeah that thing is mad you woke it up.. Love the dial! Great job!
One thing you don't need to concern yourself with is being accused of appearing "Presidental" . Especially with the standards we are seeing right now oh "blue gloved" devil. Great common sense and great video! Thanks for your endeavors!
Never heard of a gimmick capacitor before. Looked it up. Its a real thing. Love learning new things like this. Sorry to hear Sauron is taking over a lot of your radio stations. I can't see anything but bad coming from that. He's not a good person.
Shango, I watch most of your videos but never post a comment. I totally agree about what you said about the old man from Hungary. I have made similar comments about him and other similar behavior about the destruction of the core of this nation, and I got an immediate warning about my "comments".
Smoker's choice radio. Literally.
When I worked in a radio repair shop in the 80's, the one thing I could never do is replace the dial string. I left that for Walter to do. (He owned the place.)
Great job as always 👏 Thx for sharing!
Glasslinger says "J-hooks?? We don't need no stinkin' J-hooks!" A Weller gun and a blob does the job.
Your comments about George Soros just moved you to the top of my CZcams favorites! Really do enjoy and appreciate your repair videos, too! ❤
Like we need one more leftist to try to tell us how to live our lives
Awesome!! Thank you!
My guess would be that if he doesn't shut it all down, he'll add the stations to his propaganda machine to an even greater degree than they've already declined into.
He needs to go away
I'm trying to read his books and he"s unquestionably indentured to markets being swayed by illusions. Soros likes to create illusions.
@volvo09
Oh, he will. He passed the torch to his 38-year-old son. He’s just as bad or worse. His son is currently dating Huma Abedin-Hilary Clinton’s girlfriend and Anthony Weiner’s ex wife.
@@gabrielleeliseo6062 wonderful... Just wonderful.
Yes, we really need more Rupert Murdochs 😅😂
32:18 Yes, smoke is good. It's what semi-conductors are made of. ;-)
That's one good 👍 looking radio 📻. Your friend, Jeff.
This country is done for anyway. Stop worrying about it. All empires fall eventually. Do you want a good radio station? Do what I did when I wanted a good TV station: make your own. A raspberry pi can do this with ease.
When I was a young soldier, in the old "black boot" Army, we used to use old diapers, you know the real cloth type before pampers came along, to spit shin our combat boots. In the Army back then everyone above the rank of SP-4 or Corporal was very interested on how well you spit shined those old combat boots. Now days I still. Use KIWI on my black loafers but just for brush shine, it keeps the leather supple, looks good and brings back those memories of when I was a lolley SP-4 before I got my Stripes and got to stop doing grunt work,
Nice radio! I also have a couple of am sw tabletop radios
neo magnet on the back of the old speaker works great. modern headphone speakers like 20-40mm usually have the rare earth in them. they are usually glued on the back so just knock them off with a hammer
Imagine, a 10 year old experienced Abraham Lincolns assassinated in 1865, then at 80 could have listened to this radio, and traveled by airplane, and automobile. Wow, seeing a complete change in technology in thier lifetime.
Appreciate the final minutes of this on technique. A while back I showed some experimentation on the bias cell with a variable buck converter and did not get a lot of difference with the voltage 1.5~3.5 V. I think a coin cell would work fine and will be my eventual solution on my '37 Grunow which has one. Thanks for another interesting video.
I did a bias cell bypass on a Stromberg by disconnecting the bias cell entirely & hooking the middle lug of the vol control straight into the 6F5 grid, then disconnecting the cathode from ground and putting a 3.3uf cap in parallel to a 1500 ohm resistor. Been working great for years and plenty of volume and fidelity.
@@sgath92 Interesting. When I did a final checkout on the Grunow, I even had the bias cell completely disconnected and it sounded just fine. That may vary with a different circuit - IDK.
Hi, Great videos love the snark. On the tuning eye, you'll find a 1 meg resistor in the socket which will be nearly open. Replace that or just put straight B+ on it. It will help. Thanks!
👍 thank you for explaining the function of the components, just retired and this is my new hobby. Like your political view also. 👍thanks !!
That thing connected to the volume control is a bias cell battery
That set is not Philco built, Knight was a Allied radio, probably built in one of the Chicago area radio plants
Totally agree when not in use unplug it. Enjoyed video. Thankyou
great points at the end of the video thanks
That thing that looks like a small metal top hat is a 1.5 volt bias cell. In direct-heater tubes or before they developed negative grid bias from cathode current bias cells were used to keep the grid slightly negative. There is almost no current drain and I bet it still tests a little voltage.
Thanks!
So many people have no clue. Pure evil going on in this world, soon we'll have to confront reality.
Love the radio repair vids, I've been collectingntube radios & need to get them all going also.
with tuning indicators, its the phosphor that wears out not so much the cathode emission,
Thanks for another great video! This chassis looks like my 1938 vintage Stewart Warner R1915-D, except that it has no shortwave, no tuning eye and mine was a battery radio because it has a vibrator. The layout is VERY similar otherwise right down to the 41 tube. I found mine in an old farmhouse junk pile
I’ve got a 6U5 eye tube that also says 6G5 on it. The 6E5 has the same socket and uses the same tests on my tube tester. I’m not sure the difference except for the 6E5 being a half inch shorter. You might be able to substitute one for the other.
Keep up the good common-sense repair videos. I try to second-guess each step of your troubleshooting. Also keep buying parts from our friend Bill M. in Sunbury, PA. 24 years ago I sold him my Admiral TV that is on his TV parts page.
Would really like to see another one of those desert find tv ressurection vids. The ones where they look completely baked / beyond repair and you somehow manage to breathe life back into them .
Yes. In stock and ready to go when time permits and weather allows
@@shango066 🙌something to look forward to. Thankyou.
The small unknown component is a Mallory bias cell. Used to provide low negative grid voltage for the first audio tube.
Awesome restore video Shango best on CZcams!
these old radios never die, build for last
Nice pre-octal set!
The RestoreOldRadios channel did a full restoration of an identical set about a year ago.
The bias cell is used to bias the grid of the 75 duodiode-triode tube, just in series with the volume control; they could have used a cathode resistor instead as the diode sections are not used (the detector uses a separate diode-connected 76 triode - 1:17:00).
The schematic is on Nostalgia Air (Sentinel 98AE), IF appears to be 465kHz.
41 is electrically identical to 6K6 octal.
I'd try also a good speaker, the magnets may not be doing a good job there (magnetic field shunted via the armature?)
I knew someone would recognize it. I looked at every Allied set I have data on which is a lot and some were close
They could also have used a 5 to 10 meg ohm resistor and a capacitor in series with volume control, on the grid of the 75 tube and had grid leak bias. Inserting a cathode biasing resistor would up set the diode AM detector function.
@@JCWise-sf9ww True, but note that the detector uses a separate 76 tube, so the bias resistor at the cathode of the 75 would not upset anything. One could argue that a single cathode bias resistor would cost less than a capacitor and resistor for grid leak bias, but then again they used an extra tube and a bias cell (!), so cost was not the issue.
Loved the Zen smoke.
If you run D.C. B+ thru the speaker long enough wouldn't it tend to permanently magnetize the coil assy?
It would, but that's desirable in this circumstance - the speaker has two coils, one with many windings used as the choke, and another with only a few windings to move the cone with audio. The effect is minimal, because of the soft iron core.
If you keep finding small vehicles.. - you can start a car museum.. 😊 Niice video.
I guess you could experiment substituting that field coil by a coil out of a contactor, an old school relay that could be disassembled, or a solenoid from an irrigation valve. Just find one that fits in there and see what happens.
Seeing the weak #41 and the substitution of the 6AQ5 reminded me of the #89 tube, which is very close to the #41, but the grids are wired out to individual pins rather than having G3 tied to the cathode internally. One of these days I'll try it and see what happens. The #89 had some military application and seems to be a whole bunch of them around, but I have found very very few radios that use one. The #41 & #42 became the 6K6 and 6F6 respectively.
Never seen one of those Mallory cells on a uk radio, and I have a huge collection of sets from the 30's, I suppose they never made it across the pond. You need alot of patience to rewind a field coil, well done using neo magnets, I'd never have thought of it.
It looks like it could be a sentinal 98A,and the button is a bias cell.
Knight Radio - new dial string nice
Jason JJ cruiser!!! Replace all electrolytic capacitors no matter what
21:13 Sticking the magnet on the back will not give magnet field close to original sensitivity. The efficient fix is to take off the field coil magnet bracket, put a round flat neodymium magnet on the edge of the core and secure it with glue. The next step is to put the bracket back, but with couple of steel washers and longer screws. If the neodymium magnet did not fall off the core during this process, the speaker should work and look almost original.
Yes the big SCSI drive magnets take me back! WAY back when I used Apple computers more seriously I had a 'Mac II fx' connected to 5 of those giant scsi drives I got at a tech surplus flea market for next to nothing. VERY fast and cheap for the time!! Not that I expected much of that setup with an 030 processor, lol And of course they didn't last long after being used! The head amps failed one by one. Now I just have the crazy-powerful magnets and a spindle completely filled with just platters, no space in between.