Mitsubishi VS55601 convergence question

This set has poor dynamic convergence affecting two colors. (I don't remember which two though). It is however fine around the center area of the screen. I haven't been doing convergence repairs because I got burned on a few in the past and had to cut my losses and walk away from the job but with many 27" and even some 36" repairs disappearing I don't want to keep turning this work down so I took this one on. I pulled the convergence board and brought it to the shop. It has 3 STK391-020's on it. I've never seen 3 STK's on a convergence board before. I've always seen two. Whats the deal with this configuration? I'm going to replace the chips and try to check all the low value resistors on the board. The chips are cheap enough and hopefully I'll be able to identify what the resistors are supposed to be, but are there any special concerns I should be aware of before reinstalling this board. I know that this work is where the money is and I want to start doing more of these. Thanks for any assistance. Lenny Stein, Barlen Electronics.

This set could have anything of several problems, and I would not assume that the output ICs are bad. These ICs are two channel chips, where most of the later ones are 3 channel chips. The set has a removable light box and I would not try to service just the board. You need to make some checks with the chassis intact to be able to run it. PITW to approach it any other way.

I'll send you an email so you have my address and can contact me directly. I'll send you some tips.

Leonard

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