[Jamie]

Does the connection between the caps exist in later production?

[Mondial]

No it does not exist. The resistor and cap connected between the two filter positives was eliminated. There are MANY production changes in the 60 over its long product life. The .05 uf cap connected to the second filter cap may be an RF bypass added in later production.

The mica cap shown connected to the bandswitch is a padder for the police band. It may be bad but has no bearing on the current problem.

[Jamie]

Try removing the 80 tube and slowly powering up the set again. Connect your DVM set to AC volts across the problem cap and watch for any voltage rise. If you see any significant AC across the cap with no rectifier tube, then something is up with the power trans.

Ok, I pulled the 80 tube and checked voltage across the cap. No voltage at all. No overheating either. Went all the way up to 115 on the variac.

[Ron Ramirez]

There are MANY production changes in the 60 over its long product life.

Documented here:

http://www.philcoradio.com/tech/60evol.htm

[Mondial]

OK, that's good. Now reinstall the 80 tube and disconnect the wire going to the speaker field from the first filter cap. This will isolate the rest of the radio from the power supply. Slowly bring up the variac while monitoring the voltage across the filter cap and see if it gets hot.

[LASJayhawk]

Might be a good idea to pull the cap back out and make sure it isn't shorted, it may have when it overheated.

[Jamie]

LAS, this cap is new. It got pretty warm, but I never allowed it to cook.
Ron, thanks for that link. This radio has no stickers or identifying marks. I'll have to study every change to figure out what I've got.

Ok, reinstalled the tube, disconnected speaker wire, applied power. No heat. Went up to 115 on the variac. Cap got slightly warm, but nothing like before. I was able to hold it the entire test.

[Mondial]

OK, we are making progress. Now disconnect the wire from the .05 uF can cap connected to the positive of the second filter cap, and reconnect the speaker field wire. Remove the 42 tube. Slowly power up the set again and measure the DC voltage across the filter caps while checking for heating.

[Jamie]

Done. No overheating.
DC voltage on the problem cap is 445 at 115v on the variac.
DC Voltage on the second cap is 413 at 115v on variac.

[Mondial]

So now, if I understand correctly, everything is connected except the .05 uF cap and the 42 tube?

Try plugging in the 42 tube an repeat the variac test.

[Jamie]

Yes, the speaker wire has been reconnected to the problem cap, the .05 cap in the can is disconnected, and the 42 tube was removed. The only other thing I did was to examine and slightly move some of the wires running from the voice coil on the speaker - I was looking for shorts. I didn't find anything, but that doesn't mean one wasn't there.

Ok, installed the 42 tube..
Voltage on the problem cap 355
voltage on the second cap 275
no overheating

[Mondial]

Voltages look good. Are you getting any sound from the speaker?

Unless there was a short you corrected, the .05 cap appears to be the problem since it is the only thing still disconnected.

[Jamie]

Speaker crackled once or twice. I didn't actually try to tune anything in.. I'm not even sure which band is selected. I was mainly keeping an eye on that cap. I moved the voice coil wires away from the speaker chassis. They were right up against it. Insulation appeared to be intact, but it's difficult to know for sure. Prior to moving them, I did do a continuity check between all the speaker wires and the speaker chassis, and got nothing.

[Jamie]

Just checked again. Getting very low volume static from the speaker. It pops a little when I move the tone control and band switch. There is some life, so I'm sure I can get it working now. Caps are ice cold. I will add insulation to speaker wires, just for insurance.

Thanks a bunch for helping me out. Thanks a million for hanging in there. If I can ever return the favor, just let me know.

[BrendaAnnD]

Hmmm...

Mondial, is it possible that the bad .05 was setting up some kind of resonant tank circuit that was actually boosting the normal AC ripple (pulsating DC)?