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 Post subject: Magnavox 1P3822 console - needs service
PostPosted: Aug Mon 02, 2021 11:23 pm 
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Joined: Aug Mon 02, 2021 9:41 pm
Posts: 7
My wife just found a beautiful Magnavox 1P3822. I believe it's a 1969 model but am not sure.

Anyhow, she didn't notice that there was no sound on one side of the cabinet. I dug in and found the speakers on both sides are fine (in fact they're encased in styraphoam... the good kind), and the problem is that the balance isn't working on the right side. Also, the mechanism beneath the internal/external/both knob is broken and has been wired back together.

I tried jumping the wires and could not get the right side to work. However, when the sound is loud enough, it bleeds into the speaker at times.

I'm looking for someone nearby (Central Arkansas) that I can bring the board to for repair.

Thank you!


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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Wed 11, 2021 8:29 pm 
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Joined: Aug Mon 02, 2021 9:41 pm
Posts: 7
I pulled the board. This is what I found. A broken switch that had been wired back together, and a bad resistor (I believe it's a resistor).



https://www.dropbox.com/s/6deemsvljtsvj73/IMG_2565.jpeg

https://www.dropbox.com/s/a42n8c8zpn9agqf/IMG_2563.JPEG


Attachments:
File comment: Broken Internal/External/Both switch
IMG_2565.jpeg
IMG_2565.jpeg [ 593.41 KiB | Viewed 928 times ]
File comment: Bad... resistor?
IMG_2563.JPEG
IMG_2563.JPEG [ 524.39 KiB | Viewed 928 times ]
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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Wed 11, 2021 11:52 pm 
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Joined: Nov Wed 30, 2016 7:35 pm
Posts: 11105
Location: Sunbury, Ohio 43074
Yes, that certainly apepars to be a burnt resistor. Judging by the values nearby, it's in the output stage, probably an emitter resistor. My guess would be a blown transistor, but you could try just replacing the resistor. Don't get your hopes up ... they usually don't burn for no reason. You could check the outputs for dead shorts by just using an ohmmeter.

As far as the switch, those can be repaired by gluing and reinforcing with cardboard or wood slivers... but it's delicate and you should practice on some junk switch that is not important. There is a thread on here somewhere dealing with that but I cannot locate it right now.

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Preserving the hist. of electronics, one boat anchor at a time! :)
https://www.bbtvtestequipment.com


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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Thu 12, 2021 12:09 am 
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Joined: Aug Mon 02, 2021 9:41 pm
Posts: 7
Thanks for the info. Unfortunately, I have no idea how to do electronic debugging. The color coding is unreadable on top. I'll pull the transistor & if I can get it from the bottom. I don't have a schematic, and it looks like at least two of the transistors have been replaced. I'm wondering if the wiring could have been tampered with and not retuned to it's original state. It a shame. This is a gorgeous console with styrophoam-encased speakers. They look new.


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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Thu 12, 2021 1:03 am 
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Joined: Nov Wed 30, 2016 7:35 pm
Posts: 11105
Location: Sunbury, Ohio 43074
If you are going to have it fixed, it may be best to leave it alone

Try a local ham or radio/tv collectors club. They may know, or have some that can help

_________________
Preserving the hist. of electronics, one boat anchor at a time! :)
https://www.bbtvtestequipment.com


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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Wed 18, 2021 4:21 pm 
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Joined: Aug Mon 02, 2021 9:41 pm
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No luck yet finding a ham radio club (there's one in my town, but no takers). Does anyone have a schematic for a 1P3822 board?


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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Fri 20, 2021 2:33 am 
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Joined: Jan Tue 31, 2012 1:55 am
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Location: Mountains of Mourne. Ireland.
The console model number is useless for finding service information... :)

Magnavox chassis numbers are often prefixed with the letter R
The model number for the radio/tuner - amp will be pasted to a paper tag, or it (prefix R + seven digit, hyphenated) will be rubber stamped on the chassis.

Some tuner/amp model number examples.
Image

Image

:) Greg.


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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Sat 21, 2021 9:41 pm 
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Joined: Aug Mon 02, 2021 9:41 pm
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This must be it.


Attachments:
AD916856-C030-4754-A8EB-1FA80A58BF12.jpeg
AD916856-C030-4754-A8EB-1FA80A58BF12.jpeg [ 557.68 KiB | Viewed 729 times ]
451C9B38-4DBF-4BCA-BB88-13C6908DC3AC.jpeg
451C9B38-4DBF-4BCA-BB88-13C6908DC3AC.jpeg [ 552.1 KiB | Viewed 729 times ]
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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Sun 22, 2021 2:25 am 
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Location: Mountains of Mourne. Ireland.
Sams Photofact Set-1005 Folder-1B covers your model.
It's difficult to locate and there are pages missing from the expensive copy sold by the publisher.
MIA... https://antiqueradios.com/forums/viewto ... 0#p2569190

Publishers ref: https://www.samswebsite.com/en/photofac ... id/1005_1B


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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Sun 22, 2021 3:15 am 
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Joined: Dec Mon 23, 2019 5:52 pm
Posts: 625
Sams Magnavox folder 1005 covers a combo unit. The radio chassis (according to Sams), is "similar" to your unit. The 1B folder covering the radio chassis has pages numbered 1 to 13.


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Magnavox Sams 001.jpg
Magnavox Sams 001.jpg [ 710.19 KiB | Viewed 710 times ]
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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Sun 22, 2021 3:16 am 
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Joined: Dec Mon 23, 2019 5:52 pm
Posts: 625
radio chassis


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Magnavox Sams 002.jpg
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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Sun 22, 2021 4:37 am 
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Location: Mountains of Mourne. Ireland.
Steve Johnson has the Magnavox factory service literature for Series R220
it's up to rev: (revision) 14 which is close enough to work from.

pdf download $9.95
http://www.antiqueradioschematics.org/magnavox.htm

Correct listing shown below.


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x.png
x.png [ 143.63 KiB | Viewed 705 times ]
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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Sun 22, 2021 4:45 am 
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Joined: Jan Tue 31, 2012 1:55 am
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Location: Mountains of Mourne. Ireland.
Attached below is a real sketchy scan of the earlier revisions, as published by Sams.
It looks to be incomplete to me...
and I have Zero idea where it came from. lol


Attachments:
Service manual.pdf [1.67 MiB]
Downloaded 18 times
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 Post subject: Re: Magnavox 1P3822 console - needs service
PostPosted: Aug Sun 22, 2021 6:42 pm 
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Joined: Aug Mon 02, 2021 9:41 pm
Posts: 7
Thanks so much for the helpful replies! I still doubt I'll tackle this, but at least I know there's a schematic!


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