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 Post subject: 1965 Maggie console. (Newbie questions)
PostPosted: Sep Wed 22, 2021 4:00 am 
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Joined: Sep Fri 17, 2021 8:40 pm
Posts: 3
Hi all!
I'm working on my first old radio ever. It's a large Magnavox console. I picked it up for nothing at an estate sale. My ex has a similar model, and I like the way hers sounds, so getting it was an easy decision. Unfortunately, unlike hers, this one was doa. The only thing it would do was turn the record platten *very* slowly. No pilot light, no lights on the controls, no sound.

I figured maybe there would be a fuse somewhere, and it was already broken, so what the hell. From reading here and staring at the general diagrams inside the cabinet, I have learned enough to identify the major components. Some probing with my multimeter suggested the amp wasn't powering up at all. I pulled the amp and pilot light.
Jumping what I guessed to be the pins for the switch, I got it to power on.
So I pulled the chassis.
Nothing looks obviously cooked in the chassis. The selector switch appears okay. The power / volume knob works fine. I cleaned the selector switches with deoxit, and that solved that. Now if I hook the chassis and amp together, the power switch on the chassis lights up the pilot light.

... And that's all. Still no lights for the tuning gauge. Fresh bulbs in all the sockets. (I had a pack laying around, long story)

Before I wrangle the chassis back into place, I'm hoping someone can tell me what else I should be looking at / for. It seems like there must still be a problem in the chassis - but I can't find a wiring diagram for it online. There's a link in many other threads that leads back to a (now dead) link from Bill where the diagram used to be available.

Suggestions?


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 Post subject: Re: 1965 Maggie console. (Newbie questions)
PostPosted: Sep Wed 22, 2021 2:56 pm 
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Joined: Sep Fri 17, 2021 8:40 pm
Posts: 3
Ah-hah! I have found a chassis / tuner schematic at archive.org.

https://archive.org/details/BeitmansMos ... 8/mode/1up

This seems like a good place to start, at least...


OH! Duh. Obviously the panel lights aren't going to light up the way I have it. In the process of figuring out how to get the chassis out of the cabinet, I pulled them off their mounts - which are half of the circuit! Just maybe I'm in better shape than I thought. Still open to suggestions on anything I ought to check over before I put the chassis and amp back in the cabinet, though. Getting that chassis out wasn't the most fun, and I'd rather not have to do it a bunch of times, as each time I am sure I'm risking busting something.


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 Post subject: Re: 1965 Maggie console. (Newbie questions)
PostPosted: Sep Wed 22, 2021 4:28 pm 
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Joined: May Thu 14, 2015 4:15 pm
Posts: 3519
Location: Dallas, TX
The slow turntable problem would be a separate problem.
There is a link here to a similar turntable model.
https://www.antiqueradios.com/forums/vi ... 6#p3358866
Dried out lubrication is a common problem with turntables.

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Tim
It's not the Destination, It's the Journey.


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 Post subject: Re: 1965 Maggie console. (Newbie questions)
PostPosted: Sep Wed 22, 2021 11:04 pm 
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Joined: Jun Tue 17, 2008 4:11 pm
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Location: Mt. Rest, SC, USA
You can find a schematic for the amplifier & power supply from Sams https://www.samswebsite.com/en/photofact/search/index/model/A5750200. (I didn't see the amplifier chassis covered in Beitman's; just the tuner.)
I would start by replacing the electrolytic capacitors. This is old enough they probably need replacing. Good luck!

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 Post subject: Re: 1965 Maggie console. (Newbie questions)
PostPosted: Sep Wed 22, 2021 11:25 pm 
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Joined: Jan Tue 31, 2012 1:55 am
Posts: 18359
Location: Mountains of Mourne. Ireland.
Attached below is the service manual for your 12 Transistor Amplifier.

Tuner / radio chassis R207-01-??
was covered in Sams Photofact Set-790 Folder-5
and/or… Set 852 Folder-6
You may find them on eBay.

Be aware, service literature purchased direct from the publisher will not be super high-resolution.
ref: https://www.samswebsite.com/en/photofac ... h&s=Search


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 Post subject: Re: 1965 Maggie console. (Newbie questions)
PostPosted: Sep Thu 23, 2021 4:11 am 
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Joined: Sep Fri 17, 2021 8:40 pm
Posts: 3
Thanks all!

I figure I'll deal with greasing the changer once I get decent sound out of the unit.

I did get it together enough to power up the radio, and I'm able to pull in FM and AM stations, but they are very quiet, sound pretty bad, and only coming from the left (channel 2) speaker at all. I suppose recapping is in order, but that wouldn't explain the loss of an entire channel, right?

As far as caps, can I just order any old electrolytic caps with the right capacitance from Mouser or Digi-key? If not, which ones are recommended? I've done plenty of soldering in my life, but never done anything like this.


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 Post subject: Re: 1965 Maggie console. (Newbie questions)
PostPosted: Sep Thu 23, 2021 1:04 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Beaver Falls, PA. USA
Just match up the working voltage and capacity, and you will be fine. For doing work on the circuit boards, you will need a small soldering iron; many of us like to use "solder wick" to remove the solder on the leads of a component, which is being replaced.

Weak sound and the loss of one channel are typical problems caused by deteriorated electrolytic capacitors. Unlike tube equipment, solid state equipment uses electrolytic capacitors for audio coupling.

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 Post subject: Re: 1965 Maggie console. (Newbie questions)
PostPosted: Sep Thu 23, 2021 3:51 pm 
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Joined: May Thu 14, 2015 4:15 pm
Posts: 3519
Location: Dallas, TX
At least with a unit this recent you probably will not find any paper dielectric capacitors you will have to replace.
When replacing components on a circuit boards there is another aspect to try to match, the lead spacing if al all possible. Many parts are smaller these days. The parts on Digikey or Mouser do have specs on the lead spacing, so that is good.
One thing you could do to help localize the problem with one channel being dead is disconnect the coax cables that go between the tuner chassis and the amplifier, at the tuner, J312 and J313 on the tuner diagram. If you touch the center pin of the cable going to the amplifier you should hear a fairly loud hum. If you get about the same volume out of both speakers the amps and speakers are OK. There should be enough space in the cabinet to find a place for the tuner chassis without remounting it into its usual spot that would be hard to get to. Put the knobs back on, etc.

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It's not the Destination, It's the Journey.


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