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Philco 640 - Need Some Help
#2

Hi Geoff,
Voltages all look pretty good. I'd dump a signal down the If  at the cap of the IF amp (78 ) at 460kc and hear what comes out of the spkr. If that goes well then move the generator to the grid cap of the 6A7 and align the IF transformers. Seems like your LO is working as you have negative voltage on grid 1 of the 6A7. Just to be sure take a look at the voltage found grid 1 to the chassis on each 42 tubes. Should see -15vdc or so. Touch the cap on the 85 tube spkr should emit a loud buzz.

GL
Terry


Messages In This Thread
Philco 640 - Need Some Help - by Geoff - 06-29-2016, 06:07 PM
RE: Philco 640 - Need Some Help - by Radioroslyn - 06-29-2016, 07:52 PM
RE: Philco 640 - Need Some Help - by Geoff - 06-29-2016, 08:05 PM
RE: Philco 640 - Need Some Help - by Geoff - 06-30-2016, 02:37 AM
RE: Philco 640 - Need Some Help - by Radioroslyn - 06-30-2016, 07:45 AM
RE: Philco 640 - Need Some Help - by Steve Davis - 06-30-2016, 10:06 AM
RE: Philco 640 - Need Some Help - by markmokris - 07-01-2016, 11:59 AM
RE: Philco 640 - Need Some Help - by Geoff - 07-01-2016, 04:00 PM
RE: Philco 640 - Need Some Help - by Geoff - 07-01-2016, 04:01 PM
RE: Philco 640 - Need Some Help - by Geoff - 07-01-2016, 04:02 PM
RE: Philco 640 - Need Some Help - by Geoff - 07-01-2016, 04:04 PM
RE: Philco 640 - Need Some Help - by Geoff - 07-01-2016, 04:10 PM
RE: Philco 640 - Need Some Help - by Geoff - 07-01-2016, 04:16 PM
RE: Philco 640 - Need Some Help - by Radioroslyn - 07-01-2016, 07:19 PM
RE: Philco 640 - Need Some Help - by Geoff - 07-01-2016, 07:20 PM
RE: Philco 640 - Need Some Help - by Radioroslyn - 07-01-2016, 08:19 PM
RE: Philco 640 - Need Some Help - by Geoff - 07-02-2016, 01:02 AM
RE: Philco 640 - Need Some Help - by Geoff - 08-04-2016, 06:39 PM
RE: Philco 640 - Need Some Help - by Geoff - 08-04-2016, 08:08 PM
Philco 640 Shadow Meter Bulb Type - by Geoff - 08-04-2016, 07:04 PM



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