Pinbot
Williams, 1986Hey guys, looking at the MPU it looks like its burned or something? Is this something to be concerned about? Know what this section does?
I tested the continuity between all the red and then the green, so it looks like its all still connected. Are these capacitors? Any way to test if they are shot?
You can get rid of those 27 ohm sand resistors and reduce heat and damage to the board completely with this mod:
http://www.pinwiki.com/wiki/index.php?title=Williams_System_9_-_11#Using_MOSFETs_in_the_Lamp_Matrix_Circuitry
Pretty easy, if you have the tools and technique. But like Ed (GPE) says, what you see is normal. If you need the parts, Ed has those too, at www.greatplainselectronics.com. Search for IRF9Z34N.
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Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact
http://www.PinWiki.com - The Place to go for Pinball Repair Info
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