How to fix noise static Vintage Tube AM Radio amplifier section Repair tip
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- Опубліковано 20 чер 2019
- Another fine TEK Tip from D-lab electronics. This time, I show how to track down that pesty static noise (lightning crashes). You may think its just a trait of AM radio reception, however that is not always the case. This radio needed a complete cap replacement, as all radios of this era do. Normally that solves the issue. In this case the true culprit was a arching mica cap (migration) This symptom is becoming more common as radio electronics age. So, if your doing a complete cap swap on your old rig, dont forget the micas! Also featured is the arrival of the D-lab exclusive wine glasses, bearing my new logo art. If you would like one, either visit my website (Donate and get the glass) or send me a message thru comments and I will get you hooked up with one, two, whatever. Thanks to all for keeping me motivated. Logo shirts are in the works. TD
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Hey Terry, I can not get enough. Thanks to you the filthy 1939 3 band Philco floor console I got at the flea market now stands pride of place in my den. I stripped the guts out of the chassis and point to point wired it to be a clone Princeton combo amp. I retained the original on-off tone pot and the volume pot and replaced the band switch knob and the tuning knob as pilot light indicator and input jack. I call the whole rig my magic jukebox as anything can now be played through the 12 inch Weber 30 watt AlNiC0 speaker. The neighbors can appreciate my music now.
On many of FDR's speeches "Fireside chats" there's plenty of that noise to keep you awake,or at least not bored with snaps,crackle,pops.sizzles,whistles,buzzing,hissing and sometimes nothing or a different channel than what you tuned.
Today we use a cell phone to do even worse.
Great video Terry, glad you're not a box wine guy.
This is another great video Terry.
A great example of how to save time, knowing where the root of most problems occur, and so then changing the Capacitors in this case, and similar, to allow you to enjoy more wine.
Yes great work, I have my little RCA back on track, Have to wait for one tube. Everything fixed.
I currently have the same issue in a 1934 Grunow after recapping (not the micas). I am going to get back into that radio this afternoon! Thanks for the tip!
Thanks! I have a Westinghouse H-164A with the exact same problem with the exact same fix, a bad mica cap after the volume control. The “lightning” was gone after I clipped the lead, ordered a replacement today. You’re a life saver and an inspiration!
Good video! One of the radios that I repaired had an open mica cap very similar to yours
Nice job tracking sown that noise. Thanks Terry
Thank you sir for the video, I like it so much, I carry in my blood the love of vintage radios, my grandfather was received as a radio technician in 1949, I'm a passionate about repairing things. sometimes I fix radios or tv's, my only problem is that I don't know how to measure, making me to replace more parts that those really needed, i have a lot of theory, so I'm always oriented where the fault can be, (I'm not an electronics technician), I always fix them, I look for radio or tv's valve operated diagrams but It's hard to find. Keep enjoying your wines.
My greetings
Rico from CA.
I've repaired guitar amplifiers that had noisy carbon comp resistors. The amps produced the exact same snap, cackle & pops. But mica caps can cause headaches if they're not replaced. I learned my lesson :)
...THAT'S THE TRUTH-!!
New video, oh yeah! I'm doing a recap of an old Zenith 6V6 mono amp this weekend. No micas, but a plethora of wax drippers to replace!
"so that’s why, I change all the caaaaps" 😁 😂 Well done for the Video Terry, again a great troubleshooting procedure 👍
Excellent diagnostic
👍 I remember my first glass of wine too
My initial thought on the issue was SMD. But also consider the old carbon resistors in the *signal chain* as well, especially the "old roundies" (the ones with the rounded ends). They can also be a noise generator.
Your right that, in the past, most of the topics, for caps, were on the old waxies and the silver mica caps in the IF cans. Not a lot of discussion on the "domino" mica caps but some of these dominos are not actually mica; they can also be paper composition.
Nice wine glasses. I hope you are able to ramp up production and offer them to other countries sometime in the future...
Cheers,
Gostei do reparo do capacitor de mica, que no geral são difícíl de estragar, mas gostei mais dos copos personalizados D-LAB, show......
Good demo on troubleshooting. Wax caps need moved to the circular file no matter what. Mica caps are usually far more reliable than anything but ceramic discs... and in RF circuits they should be left alone if possible - sometimes they're hand picked to tune a circuit and they're thermally stable. Can't fault you for ignoring that cap. I agree with evicting the waxies on general principals because if they're not a problem now they will be soon. Also seen a lot of carbon resistors cause that kind of popping, but Allen Bradley style are typically ok... Tap Test with a chopstick usually finds that kind of problem.
Very good Terry I always enjoy a good diagnostic video and you're right about those domino mica caps. They are reliable for a very long time but after 90 years time finally takes its toll and everything has to be considered. I wonder when 90 year old ceramic caps start going bad. I have an old Philco AM FM radio/ phono console built in about 1948 its a model 48-1286. I tried to do a shango on it and resurrect it with a dim bulb tester but I don't have the patience he has hahahaha 😆 that guy is a genius. I recapped it so that it can safely take the full 120volts. Also found 13 old carbon resistors that were way out of tolerance and replaced those too. Also found an open FM primary IF transformer winding on the second IF I had to rewind using wire off of a scrapped out TV speaker voice coil. That was fun I counted about 30 turns on the transformer winding. This radio uses the same IF tubes for AM and FM and has both AM and FM windings in series inside the same IF cans. I got AM playing but FM still wouldn't work and when I held a small FM pocket radio close to the oscillator it wouldn't pick up any quiet spot from the oscillator when I sweep the tuning capacitor. I measured the B+ and it supposed to be about 335volts according to the schematic but was only getting about 140volts and the culprit was a weak rectifier tube so I replaced it with two 1N4007 diodes and that brought the voltage back to normal and now FM works. Tubes have to draw more current on higher frequency FM to oscillate and work properly and after IF and RF alignment the sensitivity is very good but FM drifts after heating and I have to move the tuning slightly. I wonder if that could be bad mica caps in the FM converter. The FM IF frequency on this radio is 9.1 mhz instead of the common 10.7. AM is 455khz
I have had the same experience with those Philips cylindrical ceramics from the 50s and 60s.
I’ve got a radio exactly like that one and I love it
In retrospect it would have been a good opportunity to use a signal tracer on the audio circuit.
I was thinking the same thing.
this cracking is mostly the mica caps, eather the square ones, or the ones in the if cans.. ... its called Mica disese!
Been burned by those micas before. They can go bad, but rare........ Nice glasses! I'm more of a beer guy though....RW
I was surprised though I have had to replace those mica caps for other reasons. I have more often, though I'm not an expert, had problems with resistors causing that problem. It is a good reminder that no component is above suspicion in these old radios. You just never know how they have been treated or how hard they have been used.
Well Terry, if the problem is the always the last thing you check, just check that first😉 But seriously, good video, thanks.
First !! He he Although I'm not a radio guy, I am thinking this one has "silver mica disease"... It's the first 30 sec of the video. And at 9:30, I find out I was onto something. The thunderstorm sound was the tip off... at least it wasn't the ones INSIDE the coils.
Dude I LOVE the wine glasses and will be getting some! Next generation glasses should have a picture caricature of you like the guy from Flannigan's restaurant. Seriously, do it! Super iconic.
Excellent idea, I have my graphics expert on the task
D-lab Electronics Awesome!
Terry, That was a cool video. I had my money on the IF cans having silver mica disease - not the mica mold cap... I've never seen one of those go bad... Good stuff....Ron
Hey Man, Thanks for the donation. I have your glass packed and ready. Hope to see the wine in your new presentations!
Ron, I believe he ruled out SMD when the static continued with the volume turned all the way down.
Cool beans my friend
nice Murphy's law demonstration....but replacing all the micas may be bad advice... micas, styrene, ceramic, they all fail but they are not failure prone and are used in tuned circuit sometimes, watchout....if you are working on a TV IF stage or an Fm tuner on a radio and shotgun those caps chances are it will never work right again even if you attemp to align it...sometimes even changing the location of the cap makes difference.... on tv there are mica caps that set the frequency of the timebases and if changed th tv will not sync until you adjust the frequency via the frequency coil or potentiometer and to verify the adjustment you "need" to have a picture but if the frequency is way off there may be no high voltage developed on the flyback so no picture...see the danger?its best to set a baseline first and then replace the waxies and lytics and then diagnose if there is a problem.
coolest channel by far in this realm of zap/\
Waxers - heh :) We call'em "potatoers" in Poland.
Wax caps is not the same as ziemnioki, you used to refill them, wax ones is not refillable.
Prawda też że było u nas z nimi utrapienie.
I think I almost have seen your video , thank you I learned a lot from you, I own several Transoceanic 600, it seems all of them have same problem, too much static noise , and statics which make it literally difficult to hear to hear the stations, you become my source of inspiration to repair them although I just started to learn but your video gave me enough courage to go ahead and changed all of the caps and the filter, however the problem of noise and filter did not go away, any idea what else I am suppose to do? if you wanted to reply please keep in mind I am 74 years old and just started to learn. Thank you again for wonderful classes.
Tube wine 🍷🎶👍
You got lucky that the Silver Mica Disease was in that cap and not in the ones on the bottom of one of the IF cans. It's no fun doing surgery on those cans to remove that cap as i'm sure you well know. 73 Doug.
I would hesitate though to routine change out of mica and ceramic caps in a HiFi tuner. Remember the RF section was aligned with the original caps and compensated for their tolerance variations. Replacing these small caps could throw the alignment off. In a low cost AA5, it not that critical but be careful with a good old vintage HiFi tuner.
I agree and usually leave them alone unless they are acting up
I have a old Hamarlund BC-794 receiver with the same crackling noise. My noise is there when I crank up the volume.
Volume set to off it's not there.
It also lost reception as well. I know the LO is working because several years ago I added a digital readout that lightly couples the LO signal (its not a direct connection) and I can see the frequency change as I tune the main or bandspread knob. I am thinking the problem is somewhere after the LO but before the audio output stage.
One more mystery of the bandit capacitor solved.
Good info, I’m working on an old Silvertone model 27 Sear’s radio now. Picking up lots of stations but there’s bad humming when turned on, probably the big filter cap, which is a a 4 in one cap. Where do I find these old caps?
I wonder if freeze spray would have identified that cap as the noise maker ?
What are those little shafts that you were turning at 1:00 ? What do they do?
I love The The. Particularly Infected from 1986. Very dark songs.
I been trying to figure this one out for a long time now. I have an alfa unitra stertone radio. It has no bass whatsoever. anything below 300hz sounds like square wave harmonics. Entire radio has been recapped and resistors are all good. if i touch one of the caps near the output tube I get a loud clean 60hz hum on the speaker. sounds really good. but if I try to play a 60hz through the radio using an fm transmitter it sounds like square wave harmonics. no 60hz at all. I don't have a clue what's going on here. AM seems to have more bass than fm but still not great. Maybe you could make a video on this?
I just bought a Farnsworth AT 10 and it was working great until I brought it home an now all there is is static and one faint radio station. All the tubes light up and I can’t think of what it might be.
Hello, I'm having a similar issue with a vintage 1953 Crosley Model E-15 WE. Any suggestions or what caps I might need power resistor? Or to you fix if shipped to you? And how much?? Only getting a couple stations but lots of static behind it... Anything helps... Thanks
Mike Guerra
Can you please tell me why the magic eye tube doesn't come on? I have a Zenith radio console it turns on but no magic eye.
what type of capacitor are you replacing the Mica capacitors with? looked like dipped polyester to me but wanting to be sure as I have not had to find a substitute to the Mica before and it looks like the radio am very slowly working on has quite a few, but as it is one made behind the iron curtain in late 1950s the parts are not so familiar to me. if you want a look at it there are a couple of videos with it in on my channel . the wine glasses look good do you ship to the Czech Republic , or czechia as it is sometimes called?
its a modern silver mica cap i also use the same brand
Ok, I know you said just change all the caps and don’t worry about it, but... I’m wondering why you didn’t do any tap testing to look for sensitive components like you usually do with the guitar amps? Thanks and thanks for the videos!
This video was requested, They wanted a more technical approach, no tapping
It's really weird a mica cap with problems, but there are
Yeah, I was expecting a flaky resistor after the first few paper caps had been replaced.
I thought it was going to be the micas built into the if cans.
Terry
Nice troubleshooting
How did you isolate your scope from the hot chassie
He no doubt uses an isolation transformer to power the radio. Then there is no problem with a hot chassis set.
Hey, so I have a Silvertone Transistor AM radio model 2061 that I just finished a cosmetic restoration on, but I’m having the same problem with it that you had with this. The difference is that I get a much louder static you can hear across the house even with the volume off. I can hear a muffled voice through the static when I tune into a station with the volume up, but I just get a loud vibrating static sound. I don’t have access to many parts though. I was trying to find out what might be wrong with it.
I have worked on 2 vintage transistor radios that had that problem- it was a noisy driver transistor in the audio stage.
Just curious what type of cap exactly did you use to replace the original 470pf mica cap with the new 500pf? Like when I go to mouser or other companies do I specify a mica cap? I'm wanting to recap my Hallicrafters S38 and those domino caps confuse me. Thanks for all you!
The cap is a 500V 500PF, 5% mica type made by SaHa
@@d-labelectronics I really appreciate that as I get more and more into the repair side. A thousand thanks
Dear Terry, I got a question.
There is a high voltage electrolytic can capacitor leaking in a circuit of my vintage unit. The vallue on this one is 16+16+16uF/450V. No schematic on the www, but now I found a simalar circuit schematic (an other brand) looks like this schematic is a revision/redraw and this capacitor says 20+20+20uF/450V. Is there a warning to look after or can I replace it with this higher vallue? The following circuit: power transformer>rectifier>capacitor 3x16uF (in my opinion a filter cap for flattening purpose) Hope to hear. Cheers
H Higgins much appreciated thanks
Wow Micas caps! Loved this vid. And I'm wondering how is the best way to communicate with you, and figure if I can send a nice looking non working Swan 350B to check. I really appreciate your response. 73 de kk4nww.
Love the vids if I sent you a car audio amp that's not working properly could you repair it.?
No. 😅
Too bad... This was no surprise tip to me, it's something I learned on the shango066 channel over ten years ago. And silver mica decease has very identifiable characteristics. If it not in IF cans it's in the Mica couple caps.
Sometimes a little old mica capacitor craps out.
Nice!! US only... :-(
Serial shotgunning. Why not tracing the crackle around with the oscilloscope....?
...there are "MICAMOLD" capacitors that LOOK like mica capacitors- but they are NOT mica capacitors-(!)
i have a video of a tv repair were it works fine with a shorted cap but fails with a correct replacement new one and its a cathode bypass lytic...can you guess why?? leaky lytic+open bypass resistor= working circuit.... new cap+open bypass resistor=non working circuit.. funny huh?
great drop of brain juice
Build a Carlson super probe........2 mins later, solved
flying j-hooks when soldering :-(
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