It's time to play everyone's least favorite game: What did he blow? (NGG edition).

While adjusting a bumper leaf switch on NGG (yes while the game was on ) I must have hit a power lug at the same time, as the game went nuts after that. After it boots and I get the test report it indicates Ground short row 5 wht-grn, and the wheel motor is broken. The wheel motor works, as it spins during start up. I've taken off J206 and J208 and tested jumping between the two with the switch edge test and I'm getting nothing on some pins and multiple on others. I'm pretty sure U20 is bad. I also used my logic probe to test the column for high pulses. Pin 1 pulses high, the others just indicate always high, except for pin 5, which indicates nothing.

Looking for advice on a good test for u20, and what else I should test before I order parts.

Can you point me towards any information on testing the LM339's?