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Can't figure out where this wire goes on Philco 37-640 - Printable Version

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Can't figure out where this wire goes on Philco 37-640 - georgetownjohn - 01-03-2025

Happy New Year Phorum Members! I am stumped on my Philco 37-640. I have a wire in the tuner/rf section that I cannot determine where to reconnect it. It was a short red wire which I replaced with a new piece of the same color. I traced it back to pin #2 on the 6a8g tube socket in the tuner/rf section. This pin connection also has two other wires. One goes to the dial light and the other jumpers over to pin #7 of the 6k7g in the tuner /rf section.
I am not smart enough to figure this on out so maybe someone can help. Since one of the wires goes to the only one wire for a dial light, I figure this terminal maybe supplying 6.3 volts, but if that is true, I still need to know where to connect that red short red wire. I have tried to attach a copy of the schematic but it tells me the file type is not allowed and failed.  Thanks---John

RE: Can't figure out where this wire goes on Philco 37-640 - morzh - 01-03-2025

Pin #2 is a one of the two filament pins. It could be the one that goes to GND (chassis). It will also go to the rest of the filaments and the pilot light.
See if the chassis connection is missing. If not, every tube except the rectifier should have that connection.

RE: Can't figure out where this wire goes on Philco 37-640 - georgetownjohn - 01-03-2025

Thanks so much for the reply.  I will look at it again but now I noticed that the original wire(about 4 inches long)would have reached over to one of the pins on 6k7g tube which is on the upper right hand side of the main chassis(Looking at the bottom) Is that possible?.  I wish I was smarter.  thanks --john

RE: Can't figure out where this wire goes on Philco 37-640 - morzh - 01-03-2025

Like I said. This is the filament. All wires for the filaments in all the tubes, except the rectifier one, are parallelled. So you will have two sets of wires going between the tubes, or one going between them and then the other going to chassis point. Whichever way they chose to connect them.

RE: Can't figure out where this wire goes on Philco 37-640 - georgetownjohn - 01-04-2025

Thanks mike, things are starting to make sense now.--John

RE: Can't figure out wire for 37-640 - georgetownjohn - 01-04-2025

morzh,  Thanks for the help and yes you were right that that  red wire and the pilot light are wired on the same pin and when I put my meter on the open ended red wire, I got continuity to chassis ground. I have also fixed my problem with the schematic file for the Philco 37-640 and so I am including it as an attchemnt since I had promised to do so earlier.  UPDATE---well it still says the file is invalid.  It has the same extension and format as other photos I have attached in the past.  Perhaps someone can advise.   Thanks again--John

RE: Can't figure out where this wire goes on Philco 37-640 - morzh - 01-04-2025

A size could matter. There is some limit, it is above 2MB, but not sure where exactly; my photos get rejected when closer to 3MB.

Your wire still could go somewhere, just to connect that something to GND. See if anything that should be GND-ed is not.

RE: Can't figure out where this wire goes on Philco 37-640 - georgetownjohn - 01-04-2025

Thanks for the feedback,  I will work on it(the schematic file) this PM and will figure out the issue.--John  I beleive that the red wire needs to go to pin 7 on the 6k7 that will feed 6.3V to the shadow meter and the rest of the tubes.---John