Philco 37-640 - Printable Version
+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: Philco 37-640 (/showthread.php?tid=20907)
+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: Philco 37-640 (/showthread.php?tid=20907)
RE: Philco 37-640 - mikethedruid - 03-07-2020
Well, the speaker works fine, and the final amp works fine. I DID have to reverse the connections to the hum bucker coil, but that was easy enough. I know the speaker works from injecting an audio signal at C44. I don't, however, have anything coming from the 2nd detector / 1st audio, so I am going to have to trace out things there. That will be a bit of a pain since to even get at that tube base I will have to remove a lot of the new condensers I put in. I think I will probably just strip out everything on that side, the IF amp and 2nd detector / 1st audio, and rewire everything, carefully making sure everything goes where it should. I did try injecting the audio at the volume control, but got nothing, so I know something is screwed up there. In good news, all the tubes lit up OK, no explosions, no smoke, no smell of something overheating, so things could be worse. I know that the filament wiring is all OK, and that I have good B+. This radio is definitely the biggest pain in the butt I have had to tackle so far.
RE: Philco 37-640 - Jake Blake - 03-07-2020
" . . . I will have to remove a lot of the new condensers I put in."
Oh no.
RE: Philco 37-640 - mikethedruid - 03-09-2020
Well, after much disassembly, retracing of circuits, rearrangement of a couple of parts on the LONG terminal strip in the IF - 2nd detector, 1st audio section, as well as tracking down a power connection problem on the final amp - power supply end, I am finally getting an audio signal through the 6Q7G 1st audio, which increases and decreases properly using the volume control. That is as far as I have gotten today, but it is something anyway. No explosions or smoke from anywhere else either, so that's a plus. Time to sit back, relax, and drink a nice cup of tea. I do a little at a time, slowly working out the errors I may have made. If I work too long I end up with a back ache from being hunched over the chassis using my lighted magnifying loop so I can see clearly enough to do the work.
RE: Philco 37-640 - rfeenstra - 03-09-2020
"a back ache from being hunched over the chassis using my lighted magnifying loop so I can see clearly enough to do the work."
He, he, he! I'm getting there too!