2 dead recapped radios
 

If you read my other thread "are recaped tube radios safe?" then you already know about the Admiral 5G22 but today I recapped a Crosley 10-135 that is also dead,no tubes glowing either. Neither radio did anything like catch on fire,sizzle crackle pop etc. I am new to tubes but the first radio I recapped works! I doubt I have a tube problem because I cleaned both units up and I did a tube swap on the admiral with no new results. Tell me if I'm right on this stuff ETR DME 503k would be .05MFD,uf,mf? ETR PPN 202k would be .002? on the big caps the arrows point to negative aka common? One thing I am thinking is the caps I used on my first recap I got local and on these last 2 radio I got them online,so I could have bad new caps? I'm posting some pics of my work please look them over and see if you guys can help a noob out btw I pulled back some of the tape and heat shrink so the solder joints can be seen. Sorry if the pics are fuzzy.

the first 2 pics are of the crosley

now the admiral that didn't work then worked then died (funny thing is when it worked it worked well)

eww super fuzzy pics I'll try again later

Damn Donny, is that a cluster of bats in that pic?

lol no I just covered the old bracket with tape and used it to help hold the new caps,it looks like alot more tape then it is

You could have a dead I.F. transformer. If that's the case, you're generally sunk. Least that's what I've always heard.Still bet its a tube.-Sandy G.

So, if the tubes arent glowing, It's not a cap problem. The filaments of the tubes are all in a series string. Its just like prewar christmas lights, if one goes out they all go out.

There is a thing called Kirchoff's Law, it says that "the sum of all the voltages in a circuit will always equal zero". What this means in plain english is that all the voltages in the string will add up to the source voltage.

Also, (thanks to ohms law) whichever part of the string has the highest resistance will have the highest voltage across it. This is always true, even if the radio is broken or shut off.

Set the meter up for AC volts, and something higher than 150.

So, chassis upside down, plugged in and turned on, (careful :D ) and check the supply voltage. Probably 110, or 120 or something.

Start moving your way around the circuit. Go all the way around. There shouldnt be anything measured across the switch when its on, (and it should be on, unlike my crappy drawing). On a glowing radio, you will find about 50 volts on the 50c5, 35 volts on the 35w4, 12 volts on the 12be6 and so on around the string. The tubes probably wont be in the same order I drew them, but that doesn't matter.

On a radio that is shut off, or has a broken switch, all the source voltage will be found across the switch. On a non-glowing radio, you will find all the source voltage across the bad part. could be a tube, a switch, or even one of the wires between the tube sockets.

good luck

jc

...and so on.

Also make sure you change out that bakelite cap with color bands...these have paper inside and are very prone to shorts, this one looks like it couples the circuit ground to the chassis....it can short even with power switched off and couple 110 volt ac to the chassis.

You can repair IF transformers with cap leakage (though that doesn't seem like the problem here) you just remove the mica sheets, shorten/adjust the internal leads to avoid shorts, adding black tape if required, then add new 80-100 pf caps on the terminals under the chassis.

I think I found my problem in the admiral I believe it is the 50c5 tube and in the crosley 50c5 and 35w4 tubes. They did not have continuity on pins 3 and 4 but my other tubes do. Oops I know I should have checked every tube once I had a problem. I've learned some stuff from these posts that I have no doubt will be usefull. Thanks for the help :) and don't worry I will be asking about other radio problems lol well till you guys get tired of hearing me noobing infact I did another recap today.... will not pick up stations but I'll leave that for another day!

the thing in the lower right that looks like a big resistor is a black beauty cap.
the test for them is to drop it in the trashcan.
if it clunks when it hits the bottom it was bad.
replace all of this type just like the paper/wax.
on a dead set look for open heaters as graphicly suggested.
a 35w4 with open heater means a b+ short or shorted/leaky filter cap.

I will replace that cap when I get some tubes.I did think it was a resistor.