Quoted from Averell:

WPC devices are a reliable and robust generation.
The Powerdriver likes to be broken because of outgassed capacitors (the big ones) and burnt GI plugs.
Especially in the Indy crow's feet are very ugly and difficult to clean at Marion and Willie.
Check if the device is complete.
Indy is a heavy pinball machine, check cabinet for broken parts and make sure the button still is firmly glued.
If it has the lost plastic, the POA moves, the ruin is damaged and jackpot board is installed (prototype speaker panel).
Under the POA is an open diode, this causes short circuits in the switch matrix. Check the DMD for failures in test mode.
PinSound can cause problems if the Powerdriver does not deliver a stable 5 volts, then there are resets during game play.
My suggestion is for PinSound and Color-DMD - separate power supply.
Check Software revision... latest is L7.
Check all the fuses if they a correct and in the right place.
Often the opto electronic can cause faulty game play, check ball throughs and Idol rotor lock.

Quoted from Ericpinballfan:

Its not hard, but its the traces on the back of the boards. Those are old to. Its not for everyone, its always best to send to a pro. As an at home DYI, I dont reccomend it.
Also, its just me, but i went with all new. For the money ive put in machine, another $500 to bulletproof was worth it.