When running solenoid test, do the solenoids fire in the correct order? If they do not you are missing one of the encoded solenoid data lines which i think is your problem.

Find the decoder IC on the driver board which is U2. Place the game in solenoid test. Using a logic probe or even a DMM check U2 pins 20, 21, 22, and 23. These four lines should be moving during solenoid test. If one is floating (no reading) than you have a lack of continuity. If one line is stuck high or low and never moves you have a short or possibly a lack of continuity.

With the game off and using your DMM on continuity beep probe and look for where the lack of continuity is. The solenoid signals start at PIA U11 Pin 10 to Pin 13, go through resistors R97-R100, out on MPU J4 Pin 1 to pin 4, In on driver board j4 Pin 6, 5, 4, and 3, to driver board decoder u2 pin 23, 22, 21, 20. Trace each line through this path.

Most common place to have a problem is going to be MPU j4, driver j4, and the U11 PIA's socket.

Andrew

I wouldn't think the coin door could have anything to do with this issue. Sounds like a flakey PIA socket, MPU j4, or driver j4.

I would repin MPU j4 since the board is corroded. Corrosion will damage the male and female connector pins. Most likely place of failure in your case.

If a controlled lamp never lights, you have confirmed it has power, and the lamp board connector is good just replace the associated SCR on the lamp board. Never lighting or always on are the symptoms for a bad SCR.

Test continuity from the bulb socket all the way to the leg of the SCR. If the line is open investigate where the break is. I would put money on a cracked solder joint on a single sided lamp board. Since your MPU battery leaked you may have damage on the lamp board (very common). The corrosion will get inside of the connector and the crimp pins will break.

If it is constantly high and never goes low there is a problem on that line. It should be mostly high with low spikes (when selected). If you can trace continuity all the way back to the PIA on the MPU and there is no breaks that leaves the PIA or some kind of short. Could still be a lack of continuity, just the pressure from the your DMM leads is making the connection.

I wouldnt think a PIA fault could be intermittant, but maybe... also shorts are rarely intermittant as well. Try swapping the two PIAs at u10 and u11. Maybe the PIA socket is flakey.

You now know where to thorougly check though.

Fanatic,

SED6's issue is on the encoded side of the solenoid signals. Sounds like your issues was past the decoder.

The the bumpers firing with slings is normal to a point in a classic bally and unavoidable. Things to help isolate flipper noise getting into the switch matrix is to have clean end of stroke and flipper button contacts. The bigger the spark, the more noise there seams to be. Sometimes the ceramic disk capacitors on the switch matrix switch can go bad as well.

Make sure game is grounded properly. The side rails and all metal should be connected to the earth ground.

Switches run at 5v and low current. I doubt you could feel it. Solenoid voltage will make you jump. Display high voltage will light you up.

Best practice is to not adjust switches with power on.