All info welcomed, new member with new purchase

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All info welcomed, new member with new purchase

Post by Cajunman on Wed Jul 03, 2013 10:31 pm

Hi, and thanks for being here (already!!)

I just acquired (bought) The American By Magnavox (yes built here in America).

It's in incredible great shape, just a few surface scratches on the very top.

And, IT WORKS! (well, partially, see below)

The FM section does pick up a few stations (there are many here in the Knoxville area), and the audio, while not 'great' isn;t bad for a radio
with ALL ORIGINAL PARTS that are now about 60 years old.
And, the turntable does turn. (no sound when I touch the stylus).

I am soo 'blown away' that it actually works, and the cabinet is in such (almost pristine?) shape that I am deciding
to either leave it all 100% original or repair to 100% functional condition.

So:

1: Opinions ?

2: If I do go to rehab on the electronics, is there a source for all the parts? (Caps, tubes, etc)

3: What are 'absolute replace' items?

I do have a very very good electronics background (component level computer, TV, etc, with 1st class FCC License), but it's been 15 years.

Any, all comments, connects, are welcome.

BTW, Happy 4th of July 2013, (In 3 hrs)

Ray Bergeron
Oak Ridge, Tennessee



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Re: All info welcomed, new member with new purchase

Post by Guest on Wed Jul 03, 2013 11:01 pm

What are 'absolute replace' items?
 
All capacitors


 
As for parts there are many good links on this site.
 
BTW......Welcome to TRF  Very Happy

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Re: All info welcomed, new member with new purchase

Post by Wildcat445 on Wed Jul 03, 2013 11:20 pm

Welcome to TRF.  We are a good bunch of folks always ready to help when we can.

You have a Magnavox console with AM-FM radio and a record player, from the early '50's era, not stereo, if I understand your post correctly.  Back in the day, Magnavox built their equipment in Fort Wayne, Indiana.  Their products are generally considered to be high quality.  The fact that it still works is no surprise to me.   I would be more surprised if it didn't, to be honest with you.  They simply do not build equipment like this anymore.

Magnavox equipment uses the chassis number for identification.  The chassis number is printed on the chassis.  You will need this number to obtain service literature for your set.  You will need service literature, containing the schematic for the set, in order to identify the different component parts of the radio and to serve as a road map of the electronics.  Attempting repair without a schematic will lead to frustration and possibly making mistakes.  

You do not mention any equipment you may have.  You will need basic soldering skills, the ability to read and interpret electronic test instruments,and the ability to read and understand a schematic.  You will need soldering equipment, a VTVM, a tube tester, a signal generator, a signal tracer, and some basic hand tool, such as side cut pliers, wire strippers, screw driver, both plus and minus types, etc.  Capacitors and tubes are available from several sources.  Each person has a preference, and this can be discussed later.  I personally avoid digital multimeters as the display "bounces" too much and can lead to confusion.  I prefer a good analog meter for testing.

I would personally not operate this set until you have taken the opportunity to remove the chassis (some sets have two or more chassis) and service them for safe operation.  I would replace all the electrolytic capacitors, all the paper coupling capacitors, check all resistors for any out of tolerance.  The resistors in the audio section are normally found out of tolerance and must be replaced.  Test all the tubes and replace any that are found weak. Clean all the switches and controls with De-Oxit or similiar.  If the set is operated with bad capacitors, possible damage to expensive or hard to replace components could occur.  Then you will need to overhaul the record player.  Often the cartridge is found defective, and the needle will need replacing at a minimum.  The drive tire on the turntalble will probably be dried up and will slip and need replacing.  The motor will need disassembled, cleaned and lubed.  The changer mechanism will need the old hard grease cleaned off and the mechanism lubed per the instructions in the service literature.  After you get the "tune-up" done on the electronics, you may find that an alignment of the tuned circuits in the "front end" of the radio will be necessary to increase the sensitivity of the radio.  We will need the chassis number and more identification of your set to be able to give specific suggestions.

That is where I would start.  Others will likely offer good ideas as well.  Good luck on your project, and enjoy your Maggie.  It should perform amazingly well after it has been serviced properly.

Regards

WC

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Re: All info welcomed, new member with new purchase

Post by Cajunman on Thu Jul 04, 2013 7:36 am

WOW, thank- you for the immediate reply. I did not expect this level of activity.
Obviously I got to the right spot on the 1st try.

OK, to expand and summarize:

I have DVMs, but also analog, which is what I will use. I totally agree that digitals are very poor when trying to diagnose problems, not knowing how the meter samples, how often, what the sample slice is or if it samples multitude of times and averages. (I actually prefer a scope, as I have spotted bad diodes in the DC)
I also have access to scope and signal generator, and know how to use both.

Got it on replacing ALL the caps.

I have already downloaded and printed the Sams Photofact and the Magnavox service guide. Thanks for having the links to these documents easy to find.

GREAT input about De-Oxit and the lube issues. That's a great place to start.

I plan on cleaning up the chassis today, weather and time permitting, and looking into all the major systems. Won't get a chance to do any real diagnostics, not probably for a while. But will start to get a over-all idea of what is ahead. I have soo many 'must-do' project on my plate this will unfortunately have to wait, probably until winter. Then I will just schedule 2-3 days of doing nothing but getting into the electronics and doing the work.

Again, feel free to make comments. I know enough to know that I don't know enough. I doubt I
will make any fatal mistakes, but probably am not as good am many of you are who have been playing with these for years as a hobby.

Keep the income coming, I'll be reading and responding.

Ray Bergeron
Oak Ridge TN

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Re: All info welcomed, new member with new purchase

Post by Guest on Thu Jul 04, 2013 11:54 am

WOW, thank- you for the immediate reply. I did not expect this level of activity.
Obviously I got to the right spot on the 1st try.


This is a great place, I'm glad it's working for you! Very Happy Very Happy 

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Re: All info welcomed, new member with new purchase

Post by Bill Cahill on Thu Jul 04, 2013 2:35 pm

Welcome to TRF.
I would replace all paper capacitors in the set, test tubes, replace electrolytics, and, if your set has the infamous rubber wiring i it, it will need to be properly replaced for the set to be safe to operate.
The dead phonograph may well be a bad crystal cartridge. Very common problem. I'd worry about the radio, first.

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Re: All info welcomed, new member with new purchase

Post by Cajunman on Fri Jul 05, 2013 9:28 pm

On the 4th I removed the turntable and the chassis.
I removed all tubes, cleaned them and the chassis and did a detailed look at
all the components.

I easily spotted a completely burned (in two) resistor, and 3 others that
look like they got really hot.

The turntable, mechanical, is in pristine condition, everything is smoothe and friction free.
And the 'needle;, is still in perfect shape.

It will be months till I will have the time to get it on the bench, but will acquire the components
(caps, resistors, etc) before hand so I can get started on the right foot.

Thanks again all.

Ray Bergeron

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Re: All info welcomed, new member with new purchase

Post by Wildcat445 on Sat Jul 06, 2013 4:49 pm

Where was the resistor located that was burned? There may be a short somewhere that caused the resistor(s) to get too hot.

Regards

WC

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Re: All info welcomed, new member with new purchase

Post by Guest on Sun Jul 07, 2013 12:24 pm

Wildcat445 wrote:Where was the resistor located that was burned?  There may be a short somewhere that caused the resistor(s) to get too hot.  

Regards

WC

Good point! By replacing the resistor you may only be fixing the result and not the initial cause!

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Re: All info welcomed, new member with new purchase

Post by Wildcat445 on Sun Jul 07, 2013 1:57 pm

I wonder how this set worked with a resistor burned in two. Could the resistor have burned when the set was last operated? I would not plug this thing in again until the cause of the resistor failure was found and repaired.

Regards

WC

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