I am having problems with my switch matrix on this game. I verified the problem is on the CPU and not the playfield wiring by removing the wiring from connectors CN8 and CN10. I used a jumper to test individual switches and when you jump pin 8 on CN8 to any of the pins on CN10, the entire row corresponding to that pin on CN10 registers all of the switches in that row instead of just the single switch. It only does this on pin 8 on CN8. I tried replacing the Q49 transistor and no luck in fixing. Any ideas to what could be causing this and how to fix? I suppose I could buy a new Rottendog board but is pretty expensive and was hoping there is a cheaper fix that I could do myself by replacing components on the board. OR, maybe someone has a used but good working one they could sell me. Rottendog refers to this board as MPU004, I sent a message to Jim Knight at Rottendog to see if he could possibly rebuild my board too, but any immediate help would be greatly appreciated. Thanks!

Is there a link or thread that explains how to test capacitors? What do I check for on those components RA11, LS244, and the 6821's? Also need to mention that this problem is intermittent, I could shut the game off come back and switches work ok then part way into game it does the error.

May be over my level of fixing. Anybody have a replacement CPU board they want to sell?

They seem to be ok, if there was a problem there wouldn't I be blowing fuses?

Bump, anyone have an extra original or Rottendog board they could sell?

No, terryb is correct, when I jumper pin 8 on CN8 to any pin on CN10 it registers all the switches in that corresponding row. You were saying that it should be a pulsed 12V signal instead of staying high. What makes the voltage high instead of pulsed? If LS244 gets too hot what is causing that? I'll replace all the column transistors for starters. Thanks!

So when I test the voltage on the collector of each transistor what lead should be on the collector and where does my other lead go to? Do I set to VDC on my DMM or??

Wouldn't a transistor other than the one on column 8 just effect that column? I replaced Q49 which is the one on column 8, so your saying it could be any if the transistors on the send side and the return side?

What is the LS244? Can it be replaced?

Sorry for all the questions, thanks for the help.

I didn't mean too if I did