The PHILCO Phorum
49-504 Reception - Printable Version

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49-504 Reception - tludka - 08-06-2023

I picked up and Philco 49-504 that had been worked on. Had several problems however I recapped it and had to replace the 35Z5 tube because it kept blowing the lamp and the heater string was out. Now I followed the alignment procedure and that that worked per the Philco data. However, I still do not receive any stations. What am I missing?


RE: 49-504 Reception - MrFixr55 - 08-06-2023

Hi Tludka,

Does your signal generator have a modulator? Looking at the instructions from the 1948-49 yearbook, did Steps 2 and 3 work? Steps 2 and 3 will fail if the oscillator section of the 7A8 is not working.

If you set the signal generator to a frequency withing the broadcast band with the modulation tone on, can you receive the tone on your set? If the above is true, try another radio that uses a loop antenna (not a ferrite loop though. If the "test" set works but the one that you fixed does not, you may have a sensitivity issue. Try replacing the 7A8 if you have another laying around (unfortunately, this is not a common tube).

Do you get a lot of static, squealing, etc. on both sets, you may have the all too typical issue where the computer, smart TV, LED or CFL bulbs, etc. obliterates the AM signal.


RE: 49-504 Reception - tludka - 08-07-2023

What I found was in the audio circuit R291 the plate resistor was why out of tolerance. Should be a 470K it was 610K. I replaced it and rechecked the alignment and everything worked fine. Thank you for your suggestions.