Hi,

I need some ideas on how to troubleshoot a Comet machine whose solenoids do not work.

Background: This machine only starts in Accounting Mode. When it was playable, we had to deal with the fact it only started in "04" mode. It was still this way when we started having problems. Recently, as we were playing the machine one of the Bumpers Solenoids actually started smoking and turned black. We replaced the solenoid with a new one but none of the solenoids work now. I have a multimeter and was able to check the pins on the Power Supply board and they all reported about 5V. We've also changed out all of the fuses, looked for any obvious loose wires, checked wire connectors, etc. We also looked for any voltage readings on many of the solenoids and the readings are 0.

We've gone through the diagnostics (CPU board says it's fine) and everything seems fine except the Solenoids.

When we start the machine, we can add credits, but the ball kicker does not kick the ball out. The flippers work randomly, but most of the time they do not.

I'm searching for ideas on how to troubleshoot this logically, correctly, etc. Any help is appreciated.

Thanks for taking an interest in the problems I'm having with Comet. I'd be lost without help.

I tested the connector as suggested. The readings were really low, or almost nothing. (.18-.2ish) on 6,7,8 to 3.

Even though I read the transistor part of the discussion, I have not done anything else. I thought I better wait for the next instructions first,

I really appreciate the help. Thanks, again.

Today's Update:

I tested both sides of the F2 fuse and the Ground on 3J3. The left side gave me no readings, and the right test showed voltage. I then pulled the F2 fuse and did a quick continuity test on it, and the fuse was bad. I placed a new 2.5A S.B. (I tested it first, and it was good) in the fuse clips and fired up the machine. The solenoids did not work. So I tested the F2 Fuse Clips again with 3J3 and only the right side had power. I pulled the fuse and it tested bad.

So in short, the fuse did not last 10 seconds when put into the machine.

What should I do for a next step.

Thanks again, for your help.

Well, I have 3 2.5A SB fuses left to burn out before I have to get more.

The Pop that burned out was the Upper Jet-Bumper. In the manual, that is #19. They System-9 Solenoid Table shows the Drive Trans as Q79 (a TIP122 which looks like it is in the right upper corner of the CPU board).

Does this seem correct?