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Trying to repair Quazar QC-29F20S w/ single horizontal line

Spending a little time at the parents over the holidays and trying to fix their TV. (Brought some dvd's home for christmas but wont do much good with no tv)

Quazar Model: QC-29F20S Problem: Single horizontal line on the screen about 60-75% the width of the screen.

I have rtical output circut. But the problem persists. Im not surgone over the board and cleaned up what appeard to be a bit of corosion on the bottom of the circuit board and fixed a few poor solder joints around what I think is the vee which where exacly the vertical output circut or the deflection yoke is. I have repaired tv's before but problem is different then others I have encountered. I did check the G2/Screen voltate and it is around 500V. Im stuck on what to check or do next. But am looking for a good schematic. Is there anywhere recomended to buy a schematic online ?

Any help would be greatly appreciated.

- Eric

Reply to
Charon
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Sorry, the message had a chunk of it misplaced, fixed the misplaced words.

Spending a little time at the parents over the holidays and trying to fix their TV. (Brought some dvd's home for christmas but wont do much good with no tv)

Quazar Model: QC-29F20S Problem: Single horizontal line on the screen about 60-75% the width of the screen.

I have gone over the board and cleaned up what appeard to be a bit of corosion on the bottom of the circuit board and fixed a few poor solder joints around what I think is the vertical output circut. But the problem persists. Im not sure which where exacly the vertical output circut or the deflection yoke is. I have repaired tv's before but problem is different then others I have encountered. I did check the G2/Screen voltate and it is around 500V. Im stuck on what to check or do next. But am looking for a good schematic. Is there anywhere recomended to buy a schematic online ? Any help would be greatly appreciated. - Eric

Reply to
Charon

I believe that Matsuchita or Panasonic is the rep for Quazar. You should give them a call to see if they will give you their distributor who can sell the service manual for your set.

You will have to troubleshoot the vertical deflection circuit for the faulty components. Most likey you will find defective capacitors, and possibly the vertical output device will have to be changed. When changing parts, it is very important to find the underlying fault before applying back the power.

Jerry G. ======

Char> Spending a little time at the parents over the holidays and trying to

Reply to
Jerry G.

I have been poking around in the circut and thus far have found one defective cap. right next to the vertical deflection IC. The ic looks like it has been getting VERY hot. When the line on the tv was on the ic would heat up fast and hot. Also the board around the ic has been discolored from the heat. Could there be other defective parts causing the ic to heat up this much or could the ic be shot ?

Im going to pull more parts around this circut and see if anymore caps have gone bad. thanks for the pointers

IC has the following part # LA7836

7M4

This person has a similar problem

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But there is no resolve on what went wrong but a few have suggested a bad IC.

Im doing some reading on this chip now for similar problems

- Eric

Jerry G. wrote:

Reply to
Charon

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