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Hey guys,

So I have a wells gardner K7203 that came in my centipede cabinet when I got it. When I first tested the monitor after I got the machine it sparked and I left it alone until I could recap it and install a new flyback transformer. After recapping and installing a new flyback I had the exact same issue. So I removed the chassis and started testing around. The main fuse was popped so I ordered a few boxes of those. I also found that Q002 (2SK2645) was all shorted together (all 3 legs just connected together internally, no visible damage) I also saw that there was a 1K resistor (R016) that looked burnt but it still measured 200 ohms I replaced it with the factory specified 1/6W size / spec. I also observed that R005 looked weird and measured weird so I replaced it as well (turns out this resistor was actually burnt open internally, small black speck on outside of the resistor body) and because those components were damaged I replaced the CS3842 IC just to be safe. Upon replacing all those components and testing around on the board some more I didn't see anything else that seemed off to me so I reinstalled the chassis into the bracket. Hooked everything up and tested for resistance. With the degauss coil plugged in and the yoke plugged in I was measuring around 30 ohms from live to neutral on the chassis connector. Out of caution I left the degauss coil unplugged and with the yoke plugged in I was getting 475 ohms which was the same as just testing the chassis itself. Turned on my camera powered it on and.... no spark! However there was no picture, I assumed this was due to me not having my game board hooked up so I powered the cabinet off (cabinet was powered up for about 24 seconds) and inserted the video signal cable. Powered the cabinet back up, went around the front of the machine and still no picture. About 19 seconds later.... ZZZZZZTTT something had fried on the chassis. I immediately switched the cabinet off and started inspecting. I couldn't see much so I pulled the chassis back out of the cab. I immediately was able to see my problem. The 2SK2645 MOSFET had absolutely obliterated itself the worst I have ever seen, the casing around the source lead was all melted and had a lot of black soot that was left on the board from it blowing up. I kept looking around for other things and the only other thing I found was that D002 (FF1003) when tested in diode mode tested 0.326V in BOTH directions. The reason for the specific length of time I had the cabinet powered up was because I was recording this whole fiasco so I would be able to catch any odd occurrences on camera which now I am glad I did record everything. Also, this time the main fuse did not blow! (it does seem to have a tiny bit of discoloration from the current / heat but is still okay)

So with all this being said. I'm looking to get some help. I will be ordering a new diode for D002, I already have a replacement MOSFET (I bought 25 of them since that's all I could find) Also, I have re-tested all of the components that I replaced and thankfully they all still test fine (R005 and R016) Unsure of how to test the IC but I also have 3 more of those plus the original that i'm not sure was damaged anyways just replaced it as a precaution.

I feel as if I have made at least some progress since the last time since at least this time the spark / zap was delayed however I would love to get this thing actually figured out.

*** All components were tested outside of the chassis before installing to ensure they 1) matched the originals pinout / value and 2) to verify that they worked how they were supposed to ****

K7203 Schematic: https://wellsgardner.com/wp-content/uploads/2016/08/K7203_13_19_inch.pdf

Thanks in advance for your help!
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