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 Post subject: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Tue 05, 2017 9:41 pm 
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Joined: Dec Tue 05, 2017 6:44 pm
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Hello, was so happy to discover this forum! I was given a Magnavox Astro Sonic stereo console for my birthday last August and am hoping someone might be able to help me with finding a part for it. Don't know how long the stereo had been sitting unused - it was in an estate sale. I cleaned the controls which got rid of most static, except for occasional LOUD intermittent static that comes from the left speaker, whether it is the radio or turntable playing. I removed the back and found two of these parts: a blue capacitor and a rod (with wires wrapped around it) attached to a plastic board which in turn is stapled to the frame of the stereo. They have connections to each speaker. They are also connected to each other and the right one has a wire running into the controls. Unplugging the terminals that ran into the left speaker from the left plastic board eliminated the static, but needless to say, I no longer have sound from that side. The blue capacitor shows " Nichicon 8 MFD 25 V". I would so appreciate it if someone could point me to where I might buy the correct capacitor or better yet, the entire assembly for this unit. I have spent a lot of time trying to understand capacitors and their ratings, but confess I'm not much wiser for my efforts. (There are times when ignorance is NOT bliss!) Thanks so much!


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Thu 07, 2017 4:50 am 
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Joined: May Sat 06, 2006 4:03 am
Posts: 2813
Location: ZIP 23831 South of Richmond, VA 25 miles down the pike.
Sounds like you are speaking of the crossover cap, non-polarized type. Post a good picture.
Bill J.


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Thu 07, 2017 3:54 pm 
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Joined: Feb Wed 04, 2015 12:26 am
Posts: 560
This is early solid state. This will need quite a bit of work before it's ready for prime time. If you are lucky, it's bad/leaky caps in the power amplifier, if not, then you make need to start looking the transistors.

The part that you are looking at is the crossover for the speakers and has no bearing on the static.


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Thu 07, 2017 5:53 pm 
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Joined: Dec Tue 05, 2017 6:44 pm
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Thank you - will try and locate the power amplifier...is there one for each speaker?


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Thu 07, 2017 7:38 pm 
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Joined: Feb Wed 04, 2015 12:26 am
Posts: 560
Yours is a 100 watt stereo power amp. Both channels in the same unit.

It should look something about like this, probably mounted on the bottom of the cabinet. However, may I ask what your level of expertise is? Early solid state can be tricky, even more so than tubes. And these units use a different type of transistor called a germanium, and you must have the schematic, no exceptions, because germaniums can be installed in two different ways.


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Thu 07, 2017 11:18 pm 
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Joined: Dec Mon 08, 2008 8:27 pm
Posts: 8106
Location: alameda,CA
Before you go further, with both channels plugged in, while its on try and adjust all of the controls, one at a time independently and see if you can it to replicate that noise. You probably have some dirty control pots and some of those pots can be difficult to get cleaner into. As in you might have to flood the controls more than a few times. Its also probably not the best idea to run this without one of the speakers plugged in as that will put additional stress on the output transistors, which during this era are really fragile things.


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Fri 08, 2017 2:39 am 
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Joined: Dec Tue 05, 2017 6:44 pm
Posts: 7
Many thanks to all of you that offered suggestions! Although I spent years in IT, supporting laptops and desktops for a fairly large company, this is my first foray into the area of vintage stereo equipment. I appreciate your giving me ideas on how to proceed from here. There may be hope for me and my Maggie yet! :D


Last edited by SJMac on Dec Sat 09, 2017 7:47 pm, edited 1 time in total.

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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Fri 08, 2017 4:55 am 
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Joined: Feb Wed 04, 2015 12:26 am
Posts: 560
My suggestion right now would be get a cheap 1970's all in one unit with phono, 8 track and radio off of Ebay and the schematic for it. You'll need tools like a voltohm meter, and use the schematic to trace out the circuits, take measurements and see how everything works.

We can guide you through the process of asking questions, especially if you take pics of what you are looking at. Once you get the basic down, then work on the Maggie.

As mentioned before, the problem with these early Solid State systems is that they are not forgiving of mistakes, and in addition to what I said earlier, the germanium transistors can be mounted in two different ways, and they have to be troubleshot differently depending on the installation.

The turntable will also need to be cleaned, all old grease removed and relubricated. You should probably go ahead replace the needle at the very least, and you can get that from Gary at thevoiceofmusic.com


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Fri 08, 2017 6:20 pm 
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Joined: Dec Tue 05, 2017 6:44 pm
Posts: 7
Clearly I have much to learn! I scoured my east Texas area for a parts/repair shop without success, so eBay it is.

To be continued...(hope I'm not in over my head!) Thanks again, y'all!


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Fri 08, 2017 6:30 pm 
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Joined: Dec Mon 08, 2008 8:27 pm
Posts: 8106
Location: alameda,CA
Those PCB boards from that era also kind of suck. I've seen so many of them where due to being so flimsily reinforced they will flex and then sometimes get a bad solder joint as a result.

With regard to the turntable what tends to go bad the most are the rubber idler wheels that are under the platter. If its all hardened up the platter will slip or spin slowly if at all. The Voice of Music site rebuilds these though.


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Fri 08, 2017 6:52 pm 
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Joined: Dec Tue 05, 2017 6:44 pm
Posts: 7
Actually, the turntable works fairly well, if a little slow at first. I did locate replacement needles and have installed one. The right speaker sounds good as does the radio. I will, however, discontinue playing the stereo until I can get the schematics and hopefully get it repaired. She's a sweet old girl - finish is in excellent shape.


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Fri 08, 2017 7:15 pm 
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Joined: Dec Mon 08, 2008 8:27 pm
Posts: 8106
Location: alameda,CA
You'll get hooked. The next step of course is to buy more. Personally I don't really like solid state sets but that's just me. Luckily the era of unit you have is still fairly cheap. In fact the museum I volunteer at has one of these that someone just dropped off. It all works but we will be lucky if we can even give the thing away.


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Sat 09, 2017 7:46 pm 
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Joined: Dec Tue 05, 2017 6:44 pm
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I can understand getting attached to these old systems. The sound is wonderful. This one weighs a ton - my burly son and grandson had a time getting it into the house. Good luck getting someone to take it from the museum! I did see one just like it on eBay that reputedly had been in Elvis' bedroom at Graceland. May have been a desperate ploy to get rid of it. :D

Thanks again for your help!


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Sat 09, 2017 8:43 pm 
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Joined: Jan Tue 31, 2012 1:55 am
Posts: 2929
Location: Mountains of Mourne. Ireland.
Your tuner (radio) chassis should be the same as this... R231-01-DA
seen here... viewtopic.php?p=2763474#p2763474 ←scroll down.

Service manual, approximately 17 pages: ebay $7.75 https://www.ebay.com/itm/MAGNAVOX-R231- ... SwR2RaCiY4
confirm your chassis number before pullin' the trigger.

The Amplifier will have a model number stamped on the chassis. I don't know which one it is.... :shock:
And... the record changer's will be stamped underneath the platter.

Elvis Presley did indeed have a Magnavox P3763 (serial number 4513).
It was sold at the Graceland auction in the late summer of 2015
http://auction.graceland.com/1971_elvis ... ot324.aspx

Aloha from Ireland. Lol
Greg.


Posting photos to a forum thread.
The skinny: viewtopic.php?p=2717120#p2717120


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Sat 09, 2017 9:23 pm 
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Joined: Mar Mon 17, 2008 5:05 am
Posts: 5022
Location: Ashhurst, New Zealand
There's a couple of YouTubes showing a guy fixing one....

https://www.youtube.com/watch?v=shAufGgaIRc

https://www.youtube.com/watch?v=hyIDGzVIWa8

_________________
Cheers - Martin ZL2MC


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Sun 10, 2017 10:02 pm 
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Joined: Dec Tue 05, 2017 6:44 pm
Posts: 7
Hey guys, I decided to reconnect the crossover cap, hoping that reseating the connections might bring on a miracle. As I was doing so, I saw a couple of wires that were touching each other on the blue capacitor side where they led into the soldered part of the cap under the connector. When I separated them and reconnected everything - that gosh-awful static is gone! Been playing it for an hour now and the Eagles never sounded better! Woohoo! (The static had been so bad that my dog would run out of the room when it occurred!)

Thanks to everyone for being so generous with your time and advice. I'm looking forward to playing my old Christmas LPs.

Best regards to y'all from deep in the heart of Texas!!
Shirley


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 Post subject: Re: Magnavox Astro Sonic Stereo 2P3763 - need help, please
PostPosted: Dec Mon 11, 2017 5:25 pm 
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Joined: Dec Mon 08, 2008 8:27 pm
Posts: 8106
Location: alameda,CA
Quote:
Elvis Presley did indeed have a Magnavox P3763 (serial number 4513).
It was sold at the Graceland auction in the late summer of 2015
http://auction.graceland.com/1971_elvis ... ot324.aspx


Oh gawd... I worked on one of those units and the quality is AWFUL! I can't believe someone paid $12,000 for it. Elvis or not its still a cheap system complete with fake plastic wood and a flimsy turntable.


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