[magicclocks]

I just got a philco console I stated above and when I first got it it had no sound at all. Total silence just wanted to see what I was looking at. I did the preliminary tests that are written in the schematic info and I was getting low volts on the first few test points. Only 200 volts instead of 250 from the rectifier ,a 5u4g. so I went ahead and replaced all the electrolytics and any other resistors it said could be bad . I also found two resistors blown. The r 315 which is listed as a screen dropping resistor 3300 ohm was burned right in half and the r 313 82,000 ohm was reading 1.5 megs after I replace them both. And I restored power the 3300 plohm resistor burned in half in about 5 seconds. I have ordered a new rectifier tube and two new 6v6 power tubes any other advice as to what could cause this I know it's a lot to think about , could it also be a bad 7h7 tube , or should I just start checking and replacing all caps attached to the resistors

http://www.nostalgiaair.org/PagesByModel...013617.pdf

[Radioroslyn]

I just got a philco console I stated above and when I first got it it had no sound at all. Total silence just wanted to see what I was looking at. I did the preliminary tests that are written in the schematic info and I was getting low volts on the first few test points. Only 200 volts instead of 250 from the rectifier ,a 5u4g. so I went ahead and replaced all the electrolytics and any other resistors it said could be bad . I also found two resistors blown. The r 315 which is listed as a screen dropping resistor 3300 ohm was burned right in half and the r 313 82,000 ohm was reading 1.5 megs after I replace them both. And I restored power the 3300 plohm resistor burned in half in about 5 seconds. I have ordered a new rectifier tube and two new 6v6 power tubes any other advice as to what could cause this I know it's a lot to think about , could it also be a bad 7h7 tube , or should I just start checking and replacing all caps attached to the resistors

http://www.nostalgiaair.org/PagesByModel...013617.pdf

Can't read that crummy schematic. Replace the caps around it and see what happens
Terry

[magicclocks]

Ok I've changed 3 or 4 and still it starts to smoke immediately I'll go ahead and do that whole section I had the tube that those resistors connect to removed and it still did it so it's got to be leaking caps I hope . Could that be why the rectifier only shows 200 volts instead of 250 too?

[John R]

Ok I've changed 3 or 4 and still it starts to smoke immediately I'll go ahead and do that whole section I had the tube that those resistors connect to removed and it still did it so it's got to be leaking caps I hope . Could that be why the rectifier only shows 200 volts instead of 250 too?

If C324 is good or has been replaced I would suspect a short in Z303 the 3rd I.F. can. Pull the cover off and check for shorts to ground. Also, check for shorts in the wiring around the 3rd. I.F. tube socket.
John

[magicclocks]

Wow really. I am getting nearly a direct short from both leads coming out of the if can near that resistor only an ohm. Seemed odd to me but in not knowledgeable enough. I'll do that. You gave me some hope now. I have about 7 ohms between both legs but each leg is nearly shorted to ground. I take it that's not the way it's supposed to be ?

[magicclocks]

I took the can off and right away the ohms went up to the meg range. I tried it and had reception right away but after 30 seconds it went out with a zap noise out the speaker. No smoke just a noise like zzz. It still actually has sound but with the volume up all the way I can still hear stations. Then I unplugged and checked that can again. Seems the wiring is fluctuating a lot dropping all the way down to 25,000 ohms . I will remove all the wires and get a good look under the terminal lug in the chassis that its connected to there are other things attached there too and its a mess but thanks for the help so far

[John R]

I took the can off and right away the ohms went up to the meg range. I tried it and had reception right away but after 30 seconds it went out with a zap noise out the speaker. No smoke just a noise like zzz. It still actually has sound but with the volume up all the way I can still hear stations. Then I unplugged and checked that can again. Seems the wiring is fluctuating a lot dropping all the way down to 25,000 ohms . I will remove all the wires and get a good look under the terminal lug in the chassis that its connected to there are other things attached there too and its a mess but thanks for the help so far

Yea, our in the right area. 7 ohms would be about the correct reading across the I.F. coils, wire to wire, but should have a very high resistance from the wires to ground. You have an intermittent short or direct short to ground either due to bad wires, or coils or trimmer caps shorting to ground. Good luck...just play with the circuitry with the power off/set unplugged and your meter to locate the source of the short. John

[codefox1]

I took the can off and right away the ohms went up to the meg range. I tried it and had reception right away but after 30 seconds it went out with a zap noise out the speaker. No smoke just a noise like zzz. It still actually has sound but with the volume up all the way I can still hear stations. Then I unplugged and checked that can again. Seems the wiring is fluctuating a lot dropping all the way down to 25,000 ohms . I will remove all the wires and get a good look under the terminal lug in the chassis that its connected to there are other things attached there too and its a mess but thanks for the help so far

Yea, our in the right area. 7 ohms would be about the correct reading across the I.F. coils, wire to wire, but should have a very high resistance from the wires to ground. You have an intermittent short or direct short to ground either due to bad wires, or coils or trimmer caps shorting to ground. Good luck...just play with the circuitry with the power off/set unplugged and your meter to locate the source of the short. John

A short or open in the IF coil or even trimmer per se would not load down the circuit but could kill the signal, so must be a a connection wire or even a shorted tube. My money would be on a wire. Follow the volts.

[magicclocks]

The resistor held up this time but the signal got very weak suddenly after it played for 30 seconds I'm going to finish all the paper caps and replace some of those wires. Many in that area are real black and hard like they were very hot for a long time I though I had some pins with nothing on them reading shorts to ground also. I'll be going through it completely tomorrow, thanks for replies. I'll try without tubes except for the 5u4g also that's new and two 6v6 tubes are new too , looks like it's going to be a slow process of elimination.

[magicclocks]

Sort of an odd thing while I wait for new cap kit to come before trying again when I test for shorts to some places . I get high meg ohms but if I lift off and check again a seconds later it will be much lower ohms and again if I lift off again dropping each time. If I wait for 10 seconds or so and try again it will be back up to meg ohms ,. Question is. Is this the caps all around leaking or my meter ?

[rghines1]

Suspect your meter leads. They take a beating over time where they flex at the jacks and probe body.

[magicclocks]

I replaced several more resistors today and a few more paper caps I had and still waiting on kit to replace about 10 .01uf caps still left. I had it playing am for about 3 minutes real strong and loud , sounded real good then it started to emit some high pitched hums and faded out. I unplugged right away. I need to finish up. I ordered all the tubes too. I think some or one of them is shorted. You think maybe that is the case ?

[Arran]

I very much doubt whether any more then one tube would have a short in it, very likely it will be the one nearest that resistor that burned up. Also tube shorts don't come and go that way, if there is a hard short between elements enough to broil a resistor then it will not normally disappear as the tube colls down. In my opinion it is almost a waste of time trying to troubleshoot a set that still has most of the original paper capacitors still in it, the old caps cause 80% of the troubles these set have. If the short comes about several minutes after the set was turned on and playing then it very likely could be a paper cap that intermittently shorts or becomes very leaky as the temperature changes.
Regards
Arran

[magicclocks]

Ok thanks for that advice. I'll update with pics and the cabinet restore. And the original philco phono that's in it still too