Possessed IGT S-Plus Haywire Deluxe Help!

[Tilt]

That's correct.  If you look at fuse in the wiring diagram you'll see it's actually labeled 0 VAC and if you follow it to page two it's the common for your 7 and 8 VAC supply. 

[Tom Bera]

Ok now I think my power supply is ok not causing the board problem. What happened was the D3 diode close to the battery literally melted off the board. The board traces are brown from the heat. What should I look at that is involved on that circuit or do you think it is just a board problem? I was going to look for another board but don't want to put it in and have that happen again. If you think the problem is just the board who would you advise getting one from?  I am kind of hesitant to get one off Ebay. Thanks for all the help you have given me. Tom B

[Tilt]

The replacement diode?  Did you install it properly?  The cathode is marked with a silver band and should be installed as shown on the component layout drawing on the circuit board.

[Tom Bera]

Yes I installed it correctly but not certain it was good. I tested it after it melted it appears to be bad. Other than a bad bad diode what could cause it to overheat? I'm at a point where I think replacing the board might be the answer but I don't want to destroy another one. Thanks Tom B

[Tilt]

Was it the correct one?  It's part of the +5VDC power supply that supplies power to most of the IC's on the MPU board.  There may be other components in the power supply that are bad as well.  Unless you want to do some more component level troubleshooting of the MPU it would be quicker and easier to just replace the entire thing.  Check with Jim at Midwest slots.