Picked up a Middle Earth. Replaced a fuse and got it working except for the Display 3rd person, and 4 switches (two pop bumpers and the two top rollover buttons). All the switches that weren't working I traced to (I believe) a faulty 74145 driver and I replaced it. I also replaced a 14511 decoder driver in the display unit. Now, I turn on the game but it no longer plays. I believe I fixed the 3rd person display...it shows all digits now. But the machine will not start a game. It is stuck in attract mode. The credit display is showing 88 88. When I drop a coin I get sound, but the credits don't change (88 88). Pressing the start button does nothing. Pressing the test button does nothing also, but I think that's because there is no door switch and the switch wires are jumpered.

I changed all the electrolytics on the aux board but that didn't help.

Not sure what I might have done since it was working before I removed the CPU. The connectors look fine. Any help greatly appreciated.

No. Drop a coin and hear a sound, but the display still shows 88 88 (all segments lit).

Using a logic probe I get signals at D11 pin 12 and E9 pin 12 when pressing the start button, but the signal doesn't change at D9 pin 3. Shouldn't D9 pin 3 change state when I press the start button?

I replaced E9 and D11. No change. Still stuck in attract mode. Coin produces sound, but the credit display isn't working, shows only 88 88. I do get output change at E9 pin 12 when pressing the start button, so I know the switch connection is good. Any suggestions to test?

I tried using the troubleshooting info in the Space Rider manual. The symptoms and flowchart didn't work for me. Something new is occurring....maybe more telling of my problem. When I left the game powered up unattended for about 20 minutes it started going crazy....activating continuously the solenoids. Was making a lot of noise so I shut it down. After it cooled down I powered it up and again, after it warmed up, it started resetting continuously. At one point even I could operate the flippers, but no switches on the playfield scored anything. I mean, the game wasn't even reset, it was just going nuts. I have a constant 5v to the MPU. I'm thinking to change C9 and C5, but don't know if I wasting my time and money on this thing.

Replaced C9. No change. Definitely starts acting up after it warms up for a few minutes. Sometimes all the lights start flashing. Sometimes the solenoids all start resetting. Sometimes sits quietly in attract mode. Not sure what to check/replace next. I think I have a project for someone else.

Sold this machine a few months ago. I'll mark the thread as resolved.