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Looking for 38-690 power transformer specs - Printable Version

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Looking for 38-690 power transformer specs - Nadanutcase - 01-15-2013

I decided to re-visit a request I made under a better thread title that may catch a few more eyes than my first ever post.

I am working on a 38-690 wherein one of the power transformers has a fried primary. This set has two power transformers and the one in question is shown as item #179 on the schematic (it supplies the audio output stage). I need to know the open circuit secondary voltage out at nominal line input so I can have this transformer re-wound. There are three different Philco part numbers listed for that item number depending on the input voltage range & frequency (32-7885 for 115V/60Hz, 32-7886 for 115V/25-40 Hz, and 32-7887 for 115/230V /60Hz) but I imagine that the design secondary voltage would be about the same for any of them at nominal input.

It was suggested that I look at Chuck Schwark's site or contact him. The data is not on his site and I've not heard back from him. Earlier today another member of the radio club here in Iowa told me he's recieved good information promptly from Chuck in the past but that he's had an open request since before Christmas, so I'm guessing that he (Chuck) may be on vacation.

So, if anyone happens to have some more detailed factory data for this set or that part OR (and I know taking this reading would be a bit of a PITA) if you have a set that uses that transformer and wouldn't mind taking a reading right at the secondary with the rectifer removed, I'd really appreciate it. You could get the reading right at the rectifier socket with the tube pulled on pins 3 & 5.

Thanks very much in advance.

RE: Looking for 38-690 power transformer specs - Chuck Schwark - 01-16-2013

Hi Dave,

Never got an email from you on this. (?) I can look it up tonight when I get home from work.
Santa mis-routed your email? Phase of the Moon? Height of the tide? :-)

I was semi-out of the loop with relatives, but not totally away. Sorry about that.

Chuck

RE: Looking for 38-690 power transformer specs - Nadanutcase - 01-16-2013

THANKS! FWIW, I sent you a message (first) via the "send and email" link here on the forum then followed up a couple days later via your (very nice) web site with a message to the webmaster via the 'contact' link. I didn't get a bounce back from either one, so if you don't find them in the respective spam filters, maybe the links aren't working.

Looking forward to your reply.

RE: Looking for 38-690 power transformer specs - Chuck Schwark - 01-16-2013

Hmmm, must be in the filter(s).

Anyway, will let you know what I find in my old Philco Dealer parts catalogues.

Chuck :-)

RE: Looking for 38-690 power transformer specs - Chuck Schwark - 01-16-2013

Dave,

I looks like Philco never made a "universal replacement" transformer for the 38-690, only the original part no. 32-7885 (7886, 7887).

None of my Philco parts catalogues show it, only a price in the parts index. I checked the 1935, 37, 38, 39-41, 45 and 1953 catalogues.

It was probably designed for this model only, as there are no other 1937, 38 or 39 models using that transformer number.

Ask here on the Phorum, if you haven't already.

Sorry I couldn't be more helpful,

Chuck

RE: Looking for 38-690 power transformer specs - Nadanutcase - 01-16-2013

OK, thanks for looking. I'm not too surprised to hear that it was unique to this set. I think my best bet will be to find someone who has a working set that would be willing to pull that rectifier and take a quick reading.