Mitsubishi WS-65819 convergence problem

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southjim's picture
Mitsubishi WS-65819 convergence problem
This is my first post. I have a 2002 model Mitsubishi WS-65819. It has two STK392-570 convergence chips that were replaced by a technician in 2010. Recently the picture suddenly went into the classic "bad convergence chips" view: curved 3D with rainbow colors across the entire screen. This time, I replaced the convergence chips and it fixed the problem EXCEPT the very lower left corner of the picture is still distorted and has a red "shwoosh". This problem occurs when I have HD component input. When I try to adjust the convergence,   and click the "factory reset", it corrects the problem for a moment then goes back to the distorted picture. The convergence grid is OK except for the lower left corner where the lines are red and curved out of the boxes and cannot be adjusted. When I do not have any input connected, the Menu comes on with a perfect picture - no distortion anywhere. In this mode the convergence can be adjusted with no problems. When I click "factory reset" (with no input connected and the Menu displayed) it goes back to the distorted picture for a moment and then back to perfect picture. I have done quite a bit of pcb soldering in the past and found replacing the convergence chips to be pretty simple. I checked the pins for continuity and they all tested positive, so I don't think it is a solder problem with the convergence chips. On my board, pin 3 on both chips is not connected to any circuit. Just for the record, I am a novice at TV electronics and repairs.  If anyone has any advice or ideas on what is going on, I would appreciate the help. Thanks, Jim  

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