Sound Blaster SB1740 not work after sparks when attach to working computer

[ktmmotocross]

Hello have this Sound Blaster SB1740 that not work after sparks when attach to working computer. I not found any short on pcie pins. measured coils. one have 6V, second 12V and other have 0V and short to ground. i try to inject but looks like straight short to ground. i inject 1V 10A but nothing gets hot on thermocam, only wires. when i removed coil i found 12V on power side.

anybody knows what is that rail for?

[прямо]

Part of a DC to DC converter for the opamps maybe? something like a boost with a charge pump if the opamps operate on +/-15V supply rails.