WPC fliptronics 2 (Black Rose)

In switch edge test I'm getting a strange issue between columns 5 and 2.

If I hit ANY switch in column 5, it not only registers there, but also the corresponding switch in column 2. For example, if I hit the switch at col5 row1, it will register as a contact with BOTH col5 row1 AND col2 row1.

It doesn't happen in reverse (activating a switch in column 2 just registers as expected).

Any ideas? Maybe a bad chip U20? Maybe a switch on col 2 is grounded somewhere?

Probably not related: also happening at this time the cannon immediately fires when a ball is loaded. The switch for the fire button is in column 3, so I'm not sure what's going on here.... but both issues started at the same time. Odd

Thanks for your reply.

I can do that tomorrow. What area of the MPU?

I forgot to mention: If I pull the green-wire switch "column" connector off the MPU, I still get an odd reaction. With only the row "orange" connector attached to the MPU -- any switch contact on column 5 actually registers as a column 2 contact. It's like column 2 is permanently activated, but only a contact to column 5 will make it register... but as a column 2 switch. No other switch registers (of course) when I pull the green "column" connector off the board.

I'll take a photo tomorrow, when I'm in front of the machine.

No acid damage, and the game was playing just fine up to this point. The batteries are about 2 months old.

I replaced a couple switches when I got the game (about 6 months ago). Nothing recent.

I adjusted two ramp switches recently : lockup entry (in column 7) and left ramp enter (column 4). Nothing in the "affected" columns 5 or 2.

One more thing: The "ramp down" switch is showing up as closed (column 5!), and in fact the ramp is up. I'll take a look at that, but I don't see that causing a "bridge" between ALL the switches in column 5 creating duplicate contact closures with those in column 2.

Thanks for the help.

IMG_5646D (resized).jpeg

IMG_5647D (resized).jpeg

That's a good idea. I'll try that.

Thanks!

Well the problem now is... it's working.

I'm sure that won't hold true forever, so when that happens I'll look at U16. I think U20 controls the switch columns, so I'll add that to the list as well.