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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
Magnavox 20MT4405\17

 
 


jbrink
New User

Jun 10, 2009, 10:18 PM

Post #1 of 5 (2584 views)
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Magnavox 20MT4405\17 Can't Post
I'm having trouble with the vertical defelction. The screen is about 1/4 of the way down on the top. It gets better and worse. It looks like is brighter at the top. I do know electronics but nothing about TVs. Any help would be greatly appreciated.



jts1957
Veteran


Jun 10, 2009, 10:59 PM

Post #2 of 5 (2583 views)
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Re: [jbrink] Magnavox 20MT4405\17 [In reply to] Can't Post
Start by resoldering the vertical output IC (and any other suspicious joints).


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Location: Far, Far Away


jbrink
New User

Jun 11, 2009, 1:36 AM

Post #3 of 5 (2576 views)
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Re: [jts1957] Magnavox 20MT4405\17 [In reply to] Can't Post
Is there any easy way to identify which IC that is? I was going to take the board and try to reflow all of the joints. How long do I have to leave it off for the flyback to discharge or how can I discharge it manually so it's safe to work on? Likw I said I have 10 years working on electronics but have never worked on a TV before. It just sucks that the set is only 2 years old and I'm having these problems. It only cost me like $120 so it'd be stupid to pay someone to fix it.


Ron.M
Veteran


Jun 11, 2009, 2:30 AM

Post #4 of 5 (2575 views)
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Re: [jbrink] Magnavox 20MT4405\17 [In reply to] Can't Post
jbrink:...


The vertical IC is attached to a heat sink & has from 7 to 13 pins...
Usually on the IC it will have LA-???? printed on it...
Try resoldering those connections FIRST...Use CARE when soldering so as to NOT create a short between pins...
You do NOT have to remove the entire chassis from the TV to fix it...
Just disconnect what you have to...
Be CAREFUL of the wiring going to the CRT...Might not be enough slack...
Slide the chassis out carefully on it's side & you'll have easy access to the top or bottom of the board..
Do NOT touch OR disconnect the heavy RED wire that goes to the CRT...
That's the one that can knock you on your a$$...
Leave the set OFF prefferably overnight to allow power supply voltages to bleed off...
The vertical IC should cost you $5.00 US OR LESS...

Hope this helps...Sly....

Later....Ron.M...Cool...
Veteran & Retired TV technician


jts1957
Veteran


Jun 11, 2009, 3:48 AM

Post #5 of 5 (2570 views)
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Re: [jbrink] Magnavox 20MT4405\17 [In reply to] Can't Post
TDA prefix also popular (TDA8172, etc.).


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Location: Far, Far Away

 
 
 


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