What was your methodology? The switch matrix is connected directly to the MPU, so the most likely cause is something wrong in the wiring circuit.

Did you verify wire colors at the switches and stop there? Or did you physically trace out the wires all the way back to the A1-J6 MPU connector? Alternatively, did you electrically trace out the wires... in other words, did you verify electrical continuity of the circuit back to A1-J6 using your DMM?

With game powered off and A1-J6 disconnected:

• Put your DMM in resistance mode and touch the two leads across pins 6 and 14 on A1-J6 connector. Then actuate switch 54 (Right Outside Rollover). If circuit is good you will see your meter read zero ohms when you close this switch; and infinity (open) otherwise.

• Put your DMM in resistance mode and touch the two leads across pins 5 and 15 on A1-J6 connector. Then actuate switch 45 (Up Kicker). If circuit is good you will see your meter read zero ohms when you close this switch; and infinity (open) otherwise.

All that being said, these are only the INPUTS for the MPU. These are not directly firing solenoids.

First verify the above two input circuits to rule out bad incoming data as the cause of the confusion.

Without going through the rest of it, that's not right.

From pin 5 to 15, with switch 45 closed, you should be reading close to 0 ohms. My fault for not pointing out the diodes... swap the polarity of the leads and read across pins 5 to 15 again.

EDIT:

This should be A1-J6, pin 6, not pin 5.

Otherwise, your continuity readings don't have any obvious red flags. I would still swap leads and read across pins 5 to 15 and across pins 6 to 14 to see if you read continuity through whole circuit when each switch is closed. Alternatively, to be absolutely sure and not worry about the DMM lead polarity, clip a little test jumper wire across the corresponding diode when taking the continuity readings.

You could also test the diodes without removal since they are wired against open circuits on the one side.

Just to clarify problem description... when you're doing the switch test, you close switch 54 and the display reads "45"? Then when you close switch 45, the display reads "54"?

So Ni-Wumpf has an MPU option that swaps switch 45 and 54 in their software side of the matrix? Ok, glad you got that figured out.

I wonder if they have that documented anyplace?

EDIT:

I looked at the Ni-Wumpf manual. Page 10:

<Game Options> Here begins a list of game specific option settings – these will correspond to the game manual itself for settings regarding DIP switches 20, 31, and 32 on the original Gottlieb CPU.

But in the Haunted House manual, these are the 3 referenced DIP switches:

20 - Novelty mode
31 - "Must Remain OFF"
32 - Background Tone

If there are some other special settings in this section, Ni-Wumpf should have it better documented - no excuse.