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nonosto

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Hello

I try to repair a 29 CRT chassis PB9929 try sync for NNC. The first issue is a a continue horizontal line, it'seems horizontal or vertical defelection , I will change for a new LA7846N , is it good?
So when I removed the old, the pink thing glue on dissipatore gone. Where can I find a new?

20201010.jpg


Do you know other things can I change (excepot capkit for the moment), I take any advice.

THX
 
You should replace that every time anyways so no big deal that the old one tore. Is the line horizontal or vertical? The problem is in the opposite circuit. So if the line is horizontal you have vertical collapse.
 
THX, this is the horizontal line, so I assume that the vertical deflection, in case what's the horizontal deflection component?

can I unmont the dissipator to clean it?

20201019.jpg
 
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I remount the LA7846N is it good?

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20201026.jpg


So I am looking for this part,, someone know ref and where can I buy it:

20201027.jpg


20201029.jpg


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For the last part what's this?
 
those look like 12v relays.

after you replaced the vertical deflection ic do you still have a solid line? or do you have vertical deflection now?
 
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why do you suspect the selector? don't just replace everything until it works... fix it based on the symptoms. do you have vertical deflection now? it also helps to post pictures or video of what your screen looks like.
 
That selector switch will move the entire screen slightly to the left, right or center based on the position of the switch, it is pry not causing the vertical collapse (Horizontal line on the screen if I read correctly)

Those relay are for switching in "S-Capacitors" to correct for geometry issues when you use different resolutions (15k, 24k, 31k). There is one relay that will bypass a linearity coil, but again this is all to correct issues on the horizontal deflection when you use different resolutions. All the relay control is handled automatically by the micro on board, switching appropriate relays for the resolution detected.

Check the path out of pin-3 of that LN7846 - that is the pin that drives the vertical deflection coil. It should go to the vertical deflection coil connector, then through R318 then to ground. Make sure there are no cracked joints.
Also, follow the path from pin 2 - that should go through an inductor, then to a large electrolytic capacitor (2200 25V I believe). That cap holds all the tank energy for the vertical deflection so replace it if it looks sketchy.
 
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