Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12, 2025) x

Thread Closed

48-482 schematic
#1

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

#2

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.
#3

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

#4

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
#5

Thanks Sean, that's the info I have now. I'm looking for something that shows the 7B6.

Eric

Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org

#6

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
#7

Thanks John, hope to hear from you soon.

Eric

Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org

#8

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
#9

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
#10

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
#11

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




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco P45-6365 Universal Transformer Instruction Manual
Can anyone guide me to where this may be found?GRG — 03:00 PM
54C Complete Teardown/Rebuild
I don't think that I have encountered a 12Z3 before, curious how it uses one of those but includes a #43, which is a 25 ...Arran — 02:17 PM
HiFi (Chifi) tube amp build - but my own design.
It's the other forum. I'm also in DIY, but mostly read there. Honestly, I kinda jumped into this without much thought to...TV MAN — 10:43 AM
Philco 71 Code 125
Hello,  I am in need of a schematic for this radio. Mine has the three separate circular tube shields and a shadow me...dconant — 08:06 AM
Stromberg Carlson 1500 Squeal
And life just keeps getting more complicated.dconant — 07:57 AM
54C Complete Teardown/Rebuild
Hello Roy, here is this one sincerely Richardradiorich — 12:45 AM
54C Complete Teardown/Rebuild
Richard, Had grabbed it already but thank you just the same.  I find myself wanting to find some way to block out the...glyphmon — 12:03 AM
54C Complete Teardown/Rebuild
Hello roy, here is a link to the schematic . Sincerely Richardradiorich — 11:54 PM
54C Complete Teardown/Rebuild
Richard, The Silvertone 2014 also is a transformerless set, so I am incorporating a 1:1 600 ohm audio isolation transfo...glyphmon — 11:37 PM
Preliminary work on wife's Silvertone 2014
Did an alignment today which was interesting.  IF alignment went great, almost all was already spot-on.  Adjusting on th...glyphmon — 11:35 PM

[-]
Who's Online
There are currently 2550 online users. [Complete List]
» 1 Member(s) | 2549 Guest(s)
Avatar

>