So, I figured the unlocked MPU would solve all of our problems on Spy Hunter; however, when I plugged the board back in, we were still getting a locked on LED.
I checked TP5 on the MPU board and it had a low voltage, about 3.9VDC. I checked the voltages off the rectifier board and they were all in spec, but the solenoid driver was low as well at TP3.
I noticed that the solenoid driver hadn’t had the recommended jumpers ran and that the cap at C23 had been replaced at some point, but with an out of spec 22,000 mfd 16v. So, I pulled the solenoid driver board, swapped out C23 with a 15,000 mfd 25v cap, ran a small jumper from the negative end of C23 to the ground path below and tied a jumper between TP1 and TP3.
Popped the board back in and Spy Hunter was off and running. Only issue left was that the sound was really low. The Cheap Squawk board was getting all five flashes, so I adjusted the on board pot along with the in coin door pot and worked loose some of the grim in the pots. Sound was back, but just chiming. So, I went into adjustment 18 and set to “03” which allows the best sound experience from the game.