The PHILCO Phorum
Model 38-17, Code 121 schematic - Printable Version

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Model 38-17, Code 121 schematic - 45philcodon - 09-20-2022

I've recently acquired a nearly perfect Model 38-17. The chassis is clean and the wood case is nearly perfect. I've noted that there is no listing of the 38-17 in Nostalgia Air or in Ron's "Philco Radio 1928-1942" bible. I believe electrically this is a 38-15.

I'm in the process of replacing caps and out-of-tolerance resistors and have run into a minor problem. The 38-15 schematic has both detector diodes connected together. My 38-17 has them separated with one dedicated to developing the AVC signal. From other schematics, I can guess the resistor and capacitor values for the AVC circuit but I would like to get the actual schematic, if possible.

Any suggestions for obtaining a schematic that matches my radio?

Thanks for your help.

Don

steve chambers - Steve Chambers - 09-24-2022

The schematic can be found here:

https://www.radiomuseum.org/r/philco_38_17t38_1.html

RE: Model 38-17, Code 121 schematic - Ron Ramirez - 09-24-2022

The RM schematic is the 38-15 schematic.

I don't recall ever seeing a 38-17 schematic or service bulletin. As you stated, the 38-15 is basically the same.

You will find better info here, and higher resolution, than that found at RM - and you don't have to pay for it, either.
https://philcoradio.com/library/download/service%20info/service%20bulletins/Philco%20Service%20Bulletin%20291.pdf

The same change in the 2nd detector circuit you described was also made to later production models of the 38-15. That change is described on page 22 of the Philco Changes in Models document, which you may download here:
https://philcoradio.com/phorum/attachment.php?aid=799

steve chambers - Steve Chambers - 09-24-2022

The schematic can be found here:

https://www.radiomuseum.org/r/philco_38_17t38_1.html

RE: Model 38-17, Code 121 schematic - Ron Ramirez - 09-24-2022

Again, what Radiomuseum has is the 38-15 schematic. Look at it closely, at the bottom. It clearly states, "Fig. 4 - Schematic Diagram, Model 38-15 (emphasis mine).

I even went to the trouble of downloading it - look closely at the bottom of the picture below:

   

RE: Model 38-17, Code 121 schematic - 45philcodon - 09-24-2022

Thank you Ron, based on what I see on my 38-17, I concluded that the 38-10 schematic matched my radio for the 75 detector circuit. Your reference to page 22 of the Philco Changes in Models document confirms this.

As always, you guys are great at pointing us less experienced in the right direction.

Don