S+ with an energized coin diverter gate solenoid full-time.

[Stayouttadabunker]

Okay...here's a rare one I need some help with.

I've diagnosed that the problem lies on the MPU because it has been swapped with known good parts and cabinets.
The gate on the coin diverter solenoid under the coin mechanism unit is stuck "on" & energized full time, even if I remove the grounding bolt in the hopper.
All the coins are going to the drop even though the hopper is nearly empty and no coins are touching the bolt.

The divertor solenoid and wiring harness I've checked out are fine because all coins inserted will drop into the hopper if I swap the MPU and chips.
There are no bent pins under the questionable MPU circuit board & the motherboard does not have any shorts.

What IC component/s on the MPU control whether or not the divertor should see an open/ closed connection of the grounding bolt in the hopper?
A triac? If so, what location on MPU would it be? 

I would be able to swap out any IC component as I have extra non-working S+ MPU boards as "Parts-Only".

Ideally it would be great to see if I can get this puppy up and running again.

Thanks!

Click on picture below to enlarge schematics...which is somewhat opposite of the problem I'm having with my MPU...>>>

[jay]

Have you just swapped the reel/game chips to see if the problem is different.

[Stayouttadabunker]

No...I swapped the chips onto a different MPU and they checked out fine after playing one spin.

When I remove the "probe" bolt from the hopper, the solenoid de-energizes and coins go to hopper.

Also vice versa, the problem MPU exhibits same energized solenoid with different chips.

I'm guessing that some triac isn't seeing this on the problem MPU or the [U21] buffer chip?

I don't know what to change.

[CR1] and [CR2] under caps [C21] & [C23} are showing a lot of heat too.

I know that if those two go out of specs, they can cause flaky circuitry problems as well.

Suspect is something on the MPU is stuck "Closed", thereby energizing the divertor gate solenoid.