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I'm working on a 48-482 and I've run into a problem. The only schematic I have been able to find shows a 6SQ7 as the first audio even though all sets have a 7B6 in its place. I have a tube diagram for the 7B6 but it would sure be a help if I had a schematic that shows the 7B6.
Does anyone know where I can get one?
Thanks,
Eric
BTW. The problem is: squeal like feedback when turning up the treble control and with a long wire antenna I can only get one local station all over the dial. Has been re-caped. Tubes and resistors replaced as nec.
Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org
(This post was last modified: 12-10-2012, 07:05 PM by Eric Adams.)
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Schematic here
http://www.nostalgiaair.org/PagesByModel...013637.pdf
Tube data here for 6SQ7, 7B6 and anything else you wish.
http://www.nj7p.org/Common/Tube/SQL/Tube...?Type=6sq7
Both tubes do the same thing, and often whatever was available was used in production and changes were not always documented.
Posts: 825
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Thanks Codefox1, The schematic is the same as I have but the tube digrams are much clearer. Everything checks out at the 7B6. I guess it's back to the trouble shooting guide.
Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org
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City: Sullivan, MO
There is a factory service manual for this model on this page although it also shows the 6SQ7. It is in DJVU format so you will need a reader.
http://www.audiophool.com/Philco.html
Sean
WØKPX
(This post was last modified: 12-11-2012, 10:35 AM by Sean.)
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Thanks Sean, that's the info I have now. I'm looking for something that shows the 7B6.
Eric
Eric
The Villages, FL
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Eric, AFAIK all the published prints show the 6SQ7, but the only difference is the pin numbers. That said, this weekend when I have some time, I'll pull a working chassis and take some voltage and resistance measurements. Maybe we can pin down the problem that way.
John
Las Vegas, NV USA
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Thanks John, hope to hear from you soon.
Eric
Eric
The Villages, FL
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6SQ7
https://www.nj7p.info/Tubes/SQL/Tube_que...?Type=6sq7
If this link above doesn't work, go directly to NJ7P's website and enter the tube your looking for
Tube Database Website:
https://www.nj7p.info/Tubes/SQL/Tube.php
Posts: 2,142
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City: Westland, MI
The schematic in the Philco Radio Library accessed at the bottom of the Home page shows the 7B6.
https://philcoradio.com/library/index.ph...year-book/
Take care and BE HEALTHY! Gary
Thought I'd point it out, even though the thread is 11 years old!
"Don't pity the dead, pity the living, above all, those living without love."
Professor Albus Dumbledore
Gary - Westland Michigan
Posts: 13,776
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City: Ferdinand
State, Province, Country: Indiana
EagleRiverMike,
Welcome.
I use Bill's (NJ7P) SQL tube database query all the time - it's much easier than getting out one of my tube manuals.
But I should mention this thread is 11 years old, and the OP (original poster) hasn't visited here in nearly two years (I hope he's ok).
--
Ron Ramirez
Ferdinand IN
Posts: 2,142
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Guess Ron and I commented simultaineously! Take care and BE HEALTHY! Gary
"Don't pity the dead, pity the living, above all, those living without love."
Professor Albus Dumbledore
Gary - Westland Michigan
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