D9200 - what is this mod?

roothorick

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I noticed that somebody modified this 27D9200 neckboard:

  • Q202, Q207, and Q210 have been removed
  • Q204, Q209, and Q214 have been removed and a jumper put in their place
  • There's a diode bridging one leg each of R236 and C210, likewise R228 and C206, R244 and C217

I haven't taken a very close look at the main board, so there may be changes there too, that I missed. The board works as-is (well, this is the monitor with a red bias but it otherwise gives a good picture). Anyone seen this mod before? What is it supposed to do?
 
Its' a Wells modification for the neck board.....they used it in production shortly afterwards.
 
Its' a Wells modification for the neck board.....they used it in production shortly afterwards.

+1...

The original design had the large resistors getting so hot that they would melt the solder and fall off of the boards. The mod cools the neck board down enough to keep that from happening.
 
yeah, apparently in some applications the neckboards got so hot that they would melt the yoke retaining clips or something and make the yokes slide off. :p

the other common problem with these being missing primary colors... it can be easily caused by the color transistors failing and/or the accompanying resistor going bad. either way, I've seen problems with the solder joints too. it's best to change them all out, then maybe dialing the color drives down. won't look as pretty but it'll be a bit more reliable in the long run.
 
My fix was to add a fan blowing directly on the neck board. If the fan was too close the image would have some slight "jiggles" but the neck board never failed after that.

That fisrt gen D9200 was a real pain in the arse.
 
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