The PHILCO Phorum
49-504 - Printable Version

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Pages: 1 2

49-504 - philco4me - 09-27-2024

Hello all
I am doing a 49-504 and in section 4 I see C401is that a 5mmf ? I did not see that when I replaced the caps.

Thank you

RE: 49-504 - philco4me - 09-27-2024

Also wheni first power on the 7a8 gets very bright more than normal not sure what I did wrong

RE: 49-504 - Radioroslyn - 09-28-2024

https://philcoradio.com/library/download/service%20info/yearbooks/1948-1949/split/Part58-Philco%20Home%20Radio%20Yearbook%201948-1949.pdf

I wouldn't loose any sleep over the 7A8 filament unless you can use it for a nightlite. It's just the cold resistance of the filament is lower than the rest so it dissipates more power in brightness than the others. When it heats up the resistance rises and filament dims. Such is the life of a fil in a series strung set.

On the 5mmf cap if it's a mica leave it paper replace.

I had one of those sets many yrs ago. Nice clean cabinet design and a good player too.

RE: 49-504 - philco4me - 09-28-2024

Thank you very much.

RE: 49-504 - philco4me - 09-28-2024

So now I have an issue where as the radio gets warmer the volume gets very low and the stations don’t come in as well. Can this be a tube ?

RE: 49-504 - RodB - 09-28-2024

Hi philco4me,

So, your issue with the low volume after warmup could be a few things. One being what you suggested, weak tube. You can do 2 things to try and narrow it down. You can substitute the tubes one at a time, and I would start with the 14B6 detector. Or create a voltage chart of tube voltages right after power-on when the tubes are cool, should take just a few minutes. Then, when the volume decreases, read the voltages a second time. Keep in mind, if it's not a flaky tube, it could be a e sistor or capacitor changing value after having voltage applied. In either case you should see a change in voltage readings.

The other issue with the 5pf cap is more than likely a gimmick cap. That's two wires twisted together with one wire soldered to the tuning condenser, and the other wire connected to the loop antenna. You may have inadvertently removed them during your restoration. (What's up with these extra wires?) Hope this helps.

RE: 49-504 - philco4me - 09-28-2024

Thank you for the help. All tubes tested strong so I will double check my recap.

RE: 49-504 - philco4me - 09-29-2024

Would a bad r204 be the issue ?

RE: 49-504 - Radioroslyn - 09-29-2024

Possible yes likely not so much.

RE: 49-504 - philco4me - 09-29-2024

I  will test that one and see. Is there anything else you can suggest ?

Thank you

RE: 49-504 - philco4me - 10-03-2024

After some adjusting I was able to get a stronger  signal but when the set gets hot and you turn up the volume it gets distorted yet when it’s first turned on it works fine. Any suggestions ?
All help is appreciated.
Thank you

RE: 49-504 - MrFixr55 - 10-03-2024

Check the cathode resistor for the output tube. If that does not resolve, get a can of freeze spray. If you can't get freeze spray, turning an air duster can upside down will give you freeze spray. With the distortion present, spray each component one at a time. DO NOT spray the tubes, they will crack.

Hope this helps.

462ron - 462ron - 10-04-2024

Hi, I would monitor the voltage on the control grid of the 50A6 pin 6. On 2 occasions on different sets I would see the control grid slowly go more positive after awhile and the sound would get weak and slightly distorted even though I had recapped it. Turned out the tube had gas or some issue even though it tested good. Make sure you replaced the C200 coupling cap on your set.

Ron

RE: 49-504 - philco4me - 10-04-2024

Thank you all. I will try both your suggestions and let you know.

RE: 49-504 - philco4me - 10-07-2024

Replaced the 50a5 and the radio plays fine. The tube was the issue. Thank you all very much for your help