Solved! Sony kp-43ht20 convergence problem

[alexpio]

Hello,
my sony kp-43ht20 projection tv has a convergence issue. I bought new ICs, pico fuses and resistors, but when I tried to remove the board, the high voltage transformer wire basically won't come off. There's any particular technique to unplug the 2 high voltage wires from the transformer or there's something else I should do? I pulled both the wire quite a bit with no success, and I'm scared to damage something. Anyone can help with a suggestion? Thanks in advance.

 

[soundguruman]

What you are doing is very dangerous, I hope you realize that.
The convergence controls are on the board, and they all have to be adjusted , one at a time, with a video generator.
When something goes wrong with the convergence circuit, the voltages are wrong, and generally the board is replaced as a unit, instead of replacing components.
When the board is repaired to component level, it is done by a highly trained person, with lots of test equipment.
then, the convergence is adjusted as above. This is not a job you should be trying to do yourself.

 

[mrtired]

Sony flyback leads usually take a can of Freon to remove. Probably easier to unclip the slack in the cable and swing the board out. Please understand that it's fragile, loaded with high voltage and easily damaged by yanking a trace off.

Not a repair for the novice, but I can understand not wanting to eat the service call on a seven-year-old 4:3 set.

 

[soundguruman]

Please don't forget that these units can store thousands of volts, even when they are unplugged from the power.

 

[kat135gato]

you can try to drain some or part of the power after making the disconnection from the porwer outlet by simply pressing the power button, but press and hold down for at least a 15 secs period (for computers is recomended 10) it will drain part of the power

try also to please touch something that is making some ground to be static electricity free at the moment of been touching that system, and BE CAREFUL sony will take no responsability if you are touching the insides of a system

 

[alexpio]

Thank you guys for your concern about dealing with high voltage, but I'm pretty familiar with it ( I used to play with Tesla coils). My problem is that I still don't know how to remove the board because that wire is holding it in. Meanwhile I did some research online, and I found out that my problem could be more about adjusting geometry than others. I was able to access the service menu with the remote, and more specifically the PJE menu, where 2 grids showed up with white and green colors. From my understanding, they should be perfectly aligned. Usually the green grid is perfectly square when there's a color convergence problem. In my case the white grid is perfectly square, while the green grid matches perfectly the white grid in the center, but curves toward the top right and left angles in the top part, and curves toward the lower right and left angles in the bottom part. Anyone knows if I can align the 2 grids with the remote? Any other suggestion will be greatly appreciated. Thanks to all.

 

[mrtired]

The unit will not be fixed until the IC's are replaced. I have never disconnected the red flyback lead to perform this repair, and I don't recommend you try. Maybe put an extension cord on your solder station?

 

[alexpio]

ICs replaced....... problem still there. Any other suggestion?

 

[mrtired]

That model also has known issues with the two stand-up modules on the signal board (I think they're called B and AB) developing bad connections. Have someone watch the set and press down on the boards - hard. If no improvement, check the fuses under the heat-sinks (they're orange, usually six of them). Also check fuses 5001 and 5002 on the G board (the power supply).

 

[The-tech]

Thank you guys for your concern about dealing with high voltage, but I'm pretty familiar with it ( I used to play with Tesla coils). My problem is that I still don't know how to remove the board because that wire is holding it in. Meanwhile I did some research online, and I found out that my problem could be more about adjusting geometry than others. I was able to access the service menu with the remote, and more specifically the PJE menu, where 2 grids showed up with white and green colors. From my understanding, they should be perfectly aligned. Usually the green grid is perfectly square when there's a color convergence problem. In my case the white grid is perfectly square, while the green grid matches perfectly the white grid in the center, but curves toward the top right and left angles in the top part, and curves toward the lower right and left angles in the bottom part. Anyone knows if I can align the 2 grids with the remote? Any other suggestion will be greatly appreciated. Thanks to all.

1st the problem to remove the terminal from the fly back is because is firmly attached to it you better follow the wire & find out it goes to a square box called high voltage divider when you find it push the wire to get deeper in to the box at the time you twist it CCW then pull it has to be released but some times takes some trys to do it right make sure do not pulled extremely hard because it can brake de the bell shape terminal at the end of the wire even when is not vital it will prevent the terminal from coming out by itself.

A word about high voltage. in this kind of TV the CRT construction prevent the CRT from holding charge for to long ( no more than a few seconds) but just a precaution make sure to have the TV removed from the AC line. then you can be sure it won't represent any risk.

About the convergence adjustment.

if you have no experience it can be painful, time consuming & frustrating try to adjust this unit because you may and with the TV in worst condition than originally,

step 1 make sure that the auto focus when is done move the red, green & blue cross around that means basically that the system has control over the position of the picture other ways you will only be wasting your time & your problem relay someplace else.
2.- check that you have at least one color (green, blue or red) geometrically good that will be your base color usually the green is it that is the case DO NOT TRY TO ADJUST THAT COLOR AS LONG IS GEOMETRICALY ACCEPTABLE. get into the convergence adjustment double check for the center of the screen that match the center rectangle then moving from the center to the edges adjust only vertical line that cross the center then do the same with the main horizontal line that cross the center then returning to the center adjust the convergence in going in concentric squares sequentially til rich the edge.

If you do not have a good base color or you make the mistake to try to adjust all... good luck. I have 30 years experience & if you do that you will face the hell trying to bring them back, it that is the case you better pay a professional tech to do it.

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