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  #1  
Old 05-01-2009, 10:50 AM
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Magnavox Color TV's

Notice few posts for Magnavox Color TV's. I adopted a T93301 and so far it's appetite has been pretty sedate (mostly tubes). I remember fixing them years ago and they could really get challenging to find some problems. Mine has the original CRT with slight green around the edges but a good picture. If anyone has another Magnavox, please let me know!
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Old 05-01-2009, 10:55 AM
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Hi from a fellow Zenith Audiokarma member! The green around the edges of your tube is 'halo' or 'cataracts' which is caused by the safety glass adhesive loosening from the front of the CRT. If you're handy and careful this can be remedied but it is somewhat risky to try.
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Old 05-01-2009, 10:55 AM
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Early Maggie color sets tend to be uncommon. They were common in my area when new. Their big weakness was flyback transformers. They tended to like them every now and again. Their picture was fairly nice. Also, Magnavox required TV Repairmen to purchase parts through area dealers. It increased cost of servicing their sets outside of Magnavox dealers.

Last edited by KentTeffeteller; 05-01-2009 at 11:02 AM.
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Old 05-01-2009, 11:25 AM
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Check horizontal output current

I remember when I first got into repairing color tv's at a small shop. The owner insisted on checking horizontal output tube current and high voltage. It appeared useless at first but I found quick over half of the sets were drawing too much current. Once these problems were remedied (alot of times after they fried the flyback) we saw few flyback problems as well as much longer damper and Horizontal output tube life. My Magnavox draws a bit over 200 milliamperes after it has been on about two hours.
I had a Motorola TS-905 for a long time (wish I still did) that never needed it's horizontal tube replaced. I guess this was a lesson well learned!
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Old 05-02-2009, 05:34 PM
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I too have a Magnavox T933. You can read all about it here:

http://www.audiokarma.org/forums/sho...highlight=T933

Right now, the chassis is sitting on top of the cabinet awaiting a new filter cap, which I've been meaning to install for over 1.5 years. It's time for me to get off my butt and fix it.
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Old 05-03-2009, 02:33 PM
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T933 Flyback transformer

I just looked at the flyback in my T933. It has the original flyback and shows very little signs of distress. I remember (actually looked in old service notes) and found these sets tended to have yoke problems more than flybacks. Also tuner notes seem to be pretty frequent.
I remember the RCA sets with the burning flybacks and the later ones with punctured HV plastic cups.
Gotta say they were ALL easier to keep running than the LCD's and Plasma's of today!
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Old 05-03-2009, 03:29 PM
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A friend of mine who runs a shop claims he fixes a good many LCD's and plasma's by replacing swollen caps and resoldering bad connections. I have not gotten that lucky. Granted, I've only had a few flat panel TV's; but, I had no luck repairing them. Way too many large surface mounted IC's and other SMT parts for my liking.
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Old 05-03-2009, 06:36 PM
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LCD & Plasma repairs

I see a lot of the Polaroid and Insignia with bad capacitors. On Plasma I usually see one of either X or Y main power supply modules bad. It seems heat does this more than anything. If the module is available from a stripping organization (buys warranty return sets and parts them out, generally they are reasonable to repair. I had one plasma where the main power module was only available new and cost nearly one third of the original set cost.
And don't forget a well aimed football into a LCD screen. This is common during football season! Seems the CRT sets took it pretty good as long as it didn't knock them off the stand. LCD's aren't so forgiving.
Give me a good old CRT anyday!
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Old 05-03-2009, 07:28 PM
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Quote:
Originally Posted by radiotvnut View Post
A friend of mine who runs a shop claims he fixes a good many LCD's and plasma's by replacing swollen caps and resoldering bad connections. I have not gotten that lucky. Granted, I've only had a few flat panel TV's; but, I had no luck repairing them. Way too many large surface mounted IC's and other SMT parts for my liking.
I can't speak for LCD TVs, but I've had good luck with LCD monitors that have failed. Most of the faults are in either the solder joints on the backlight inverter - or it (the inverter) just pops its fuse. Have recently resurrected three at work that just needed a fuse and they're still chugging along. I figure they get one free fuse replacement; any more than that and I'll have to start looking for problems.

-Jim
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  #10  
Old 05-03-2009, 08:53 PM
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Quote:
Originally Posted by Zenith26kc20 View Post
And don't forget a well aimed football into a LCD screen. This is common during football season! Seems the CRT sets took it pretty good as long as it didn't knock them off the stand. LCD's aren't so forgiving.
I was shopping a local Goodwill to pick up a few cheap VCRs (was after a TV modulator circuit that I could move to channel 2 and or 6). saw a flat panel set for $50, turned it on and saw only psychedelic colors, and could see that the panel was cracked all over. I'd say that it was totaled, and $50 would be too much for parts...

As for CRT set abuse, when Howard Cosell did football games, some bars would have a raffle to pick a patron to toss a brick at a cheap used POS TV at the time (probably a set we'd want for our collections today ) when Howard was on the screen during the football game.
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Old 05-03-2009, 10:54 PM
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To further throw things off topic, today on the local freecycle there is a 50" RCA DLP "needs color wheel and bulb". Bryan isn't interested.
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  #12  
Old 05-04-2009, 06:19 PM
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Quote:
Originally Posted by radiotvnut View Post
A friend of mine who runs a shop claims he fixes a good many LCD's and plasma's by replacing swollen caps and resoldering bad connections. I have not gotten that lucky. Granted, I've only had a few flat panel TV's; but, I had no luck repairing them. Way too many large surface mounted IC's and other SMT parts for my liking.
At work I've repaired more than my fair share of Samsung LCD TVs, and Dell and other off-brand LCD monitors. I'd say about 80% of the time the problem is bloated electrolytic caps on the inverter board. Samsung uses the cheap CapXion brand of capacitors - I've been saving them all in a ziplock bag just to see how many I can collect.
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Old 05-05-2009, 05:04 PM
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Saving dead parts

Boy does that bring back memories! When I worked at nite during high school at an automobile radio repair place we put all the dead transistors in a big glass jar. It would fill rather quickly with mostly RF transistors (you would think outputs). We had a great time fixing those old radios back then.
Another quick note.... I just rechecked the Maggies horizontal out current. Afte a few hours on today it's 197 milliamperes! Soon I'll get into the vertical warm up jutter!
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Old 06-17-2009, 01:39 PM
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Maggie gets a treat!

Pulled the CRT the other day and it's off to Scotty at Hawkeye! The halo didn't bother me but the red gun was getting sleepy so.....
It gives me another chance to change some vertical capacitors that are getting sleepy too!
It'll have a Channel Master D2A set top box waiting when it is reassembled!
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  #15  
Old 06-17-2009, 01:45 PM
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I hope the rebuild goes well! I too am an owner of a rectangular color Maggie, I can't remember off the top of my head the chassis number ("the backwards chassis"). It is a '65 Astro Sonic combo unit in a gorgeous french provincial cabinet. I have to restore it, right now it just sits. I've had it longer than I've known how to work on color tvs and it broke a while ago. I now know what to do and am not afraid to tackle it anymore. In fact, it has some pretty simple stuff wrong. Let's see yours in action once the CRT is back in!
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Last edited by zenithfan1; 06-17-2009 at 01:52 PM.
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