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?

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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.

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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.

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