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42-321 model variations, schematic needed - Printable Version

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42-321 model variations, schematic needed - FStephenMasek - 10-08-2009

I am working on a 42-321. If the refinished cabinet did not looks so nice, I probably would have thrown it out by now. I had to replace all of the rubber wiring. I only get one station, the strongest local one, all across the dial. It would be helpful to have an accurate schematic to debug it, but the Rider's one is some sort of generic version for multiple models. Philco also liked to change things with run numbers. Does anyone have something better than the rider's schematic? I've rewired more complex radios, but I may have made a mistake, or I could have a bad component(s) I have not yet found. The audio is just fine, except for a speaker buzz.

Re: 42-321 model variations, schematic needed - Sean - 10-09-2009

Hi Stephen,

The info in the 1942 Philco RMS Yearbook appears to be exactly the same as what is in Rider 14-18 and 14-19. It sounds like your oscillator is not oscillating. Have you checked voltages around the 7A8, checked continuity of the oscillator coil, cleaned the pins on the tube and the socket contacts?

Re: 42-321 model variations, schematic needed - Guest - 10-30-2009

The schematic on Rider 14-19 is a close match to my 42-321 Code 121. Also, the parts list and parts placement diagram on the same page matches my radio. Of course, your's could be the variation.

Good luck,
Perry

Re: 42-321 model variations, schematic needed - FStephenMasek - 11-08-2009

Guess what? Some were made with the center posts of the first four tubes connected to the chassis, not to B-. I am working on one, and bought a parts radio yesterday, and both were made with those center posts connected to the chassis (original wiring). Both of the chassis I have were identical, and have otehr variations from the Rider's schematic. The schematic on Rider's is apparently just one version of the radio.

Re: 42-321 model variations, schematic needed - PTurney - 11-09-2009

Hi,

Agree with Sean, the oscillator is almost certainly not oscillating.

Paul

Re: 42-321 model variations, schematic needed - FStephenMasek - 11-11-2009

Yesterday, I took the 11" x17' scheamatic I had printed, and went through the chassis wire by wire, and component by component. I again confirmed that I had not made any error replacing almost all of the wires, the capacirtors, and several of the resistors. I resoldered a few connections, and cleaned or recleaned tube pins. I tested the 7A8, and replaced it with a better one I had in another radio (it was weak in the amplifier section, OK in the oscillator section). I set-up to align it, and set the IF cans, then found that it was still not oscillating, as grounding the oscillator section of the tuning gang capaciator did not make any difference. I then decided to parallel the oscillator coil from the parts radio with the one in it, and that showed that the original oscillator transformer was bad! I changed the transformer, and the radio worked OK. However, I was still not finished, as the original speaker had a bad buzz. I replaced it with the speaker from the parts set, and it sounds nice, and picks up many stations very well!

I don't know why the right side of the photos are cut off on this forum, but you can see the complete photos on my Photobucket account - FStephenMasek.

[Image: http://i269.photobucket.com/albums/jj77/FStephenMasek/Picture006-5.jpg]

[Image: http://i269.photobucket.com/albums/jj77/FStephenMasek/Picture014.jpg]

[Image: http://i269.photobucket.com/albums/jj77/FStephenMasek/Picture008-7.jpg]

[Image: http://i269.photobucket.com/albums/jj77/FStephenMasek/Picture001-9.jpg]

[Image: http://i269.photobucket.com/albums/jj77/FStephenMasek/CopyofPicture002.jpg]

Re: 42-321 model variations, schematic needed - Joe Rossi - 11-11-2009

Stephen, This is one gorgeous radio. Congrats!

Re: 42-321 model variations, schematic needed - FStephenMasek - 11-12-2009

Thanks! I would guess that there are not many restored ones, as replacing the wiring coated with brittle old rubber which is flaking off takes lots of time. I also used over 15' of de-soldering braid on this radio.

I also rewrired a Philco 41-250, but am not yet finished with the cabinet and alignment.