SuperBee4406
New member
I have a MCR 90412 Rev C power PCB I am trying to get working for my Spy Hunter. Under no load the Board seems to work fine producing +5. But when I hook up the two big connectors and turn on the cab, R111 begins to slowly smoke. The board is still producing +5. Here is what I did to the board. I installed a Bob Roberts rebuild kit. I checked for shorts in all diodes and transistors. Its not the cab, because I am testing this PCB in my Demo derby, that has a fully working MCR board in it. The cab plays fine with that PCB in it. So the problem is in the MCR board itself. I would like to get this board working and I don't want to install a switcher in the cab.
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