Working on an EBD LE project machine. I have verified all voltages are within tolerance on every board (rectifier, SDB, MPU, Lamp, Aux Lamp and S&T).

Game now boots into attract mode no problem - verified 7 flashes on the MPU. When I run a coil test, not all of my coils are firing. I go to start a game and the middle drop target instantly drops, and the outhole coil will not eject the ball into the shooter lane.

I went into the test mode and turned all lamps on. This fires the Solenoid Expander Board on and off also. I can manually fire all coils, and have verified most work. However, I don't get anything from Q17 and Q18. To manually fire, I grounded a jump line in the backbox and touch to each transistor.

Rectifier board was replaced. All new connectors installed on Rect Brd. S&T sound board from recapped and is working now. I am waiting on new conectors for the MPU, and SDB because most old Ballys need them.

Any thoughts on what to check next? Thanks in advance.

The header pin on the SEB was a mess. Had wires soldered directly to it. I replaced the header pin and connector. My 555 lamp is nice and bright. I will reflow the solder on the relay on the SEB. During test mode, it does "click" and off as opposed to "buzz"

Wondering if my MPU has some issues....I started a game last night. When I hit the switch for the lower pop bumper, the top left one fires.

I know for sure the outhole kicker coil is controlled by the SEB. Connector is wired properly.

Verified the SEB is wired properly. +43VDC to pins 3 (gnd) and 9.

Should there be a jumper wire from pin 4 to pin 9 or is that internal on the SEB? Schematic shows a jumper.

Still no luck

Repinned all the playfield connectors going to the SDB and MPU. Game boots and plays fine now.