If this is one of the typical eBay project games then STOP. I've seen some literal "shockers" lately with some horrendous board hacks and poor repinning. I'd take a few steps back and if you have repinned any connectors, don't assume they were correct to start off with. It sounds to me like the wiring of the coils is incorrect and by wiring the coils incorrectly, you can blow the diodes on the coils. What I would expect to see is the 1 AMP SloBlo fuse protecting the SD board. Go through each coil and measure the resistance. check the wiring to the coils.
J2 of the Power Supply should not be blowing coils. J1 is for the playfield, and it has your solenoid power and returns. If this is wired incorrectly, it could cause havoc with the SD board.
where are you located ?
