Black Knight 2000 upper playfield pop bumpers dead
All three pop bumpers on the upper playfield of my Black Knight 2000 have stopped working. They don't fire at all — the ball rolls through the pop bumper area with no reaction. The lower playfield pop bumpers (if there are any — I'm not 100% sure on the layout) and all other solenoids seem to work fine. Flippers, slingshots, kickout holes — everything else fires normally.
I checked the fuses and they all look good visually. In the solenoid test, I can hear the pop bumper coils fire, so the driver board seems okay. But during actual gameplay, they just don't react to the ball.
Could all three switches have failed at the same time? That seems unlikely. What else could cause all the upper pop bumpers to fail together?
yemons·3/21/2026★ 1 Answer
Great diagnostic observation — the fact that the pop bumpers fire during the solenoid test but not during gameplay tells you the coils and drivers are fine. The problem is on the switch detection side. All three pop bumpers failing simultaneously in gameplay while still passing the coil test almost certainly points to a problem in the switch matrix that is common to all three pop bumper switches.
On WPC games like Black Knight 2000, the pop bumper switches (the leaf-type spoon switches under each bumper skirt) are all on the same switch matrix column or row. If the column driver transistor or the row input on the switch matrix chip has failed, the CPU can't see any of those switches closing. Check the switch test in the diagnostic menu — manually activate each pop bumper switch by hand and see if the game registers them. If none of them register, trace back to the switch matrix on the CPU board. Look for a bad diode on one of the pop bumper switches that could be shorting out the entire column — one shorted diode can kill detection for every switch in that column. Replacement diodes (1N4148) are available at any electronics supplier, or grab a bag from Marco Specialties.
Also inspect the pop bumper switch assemblies themselves — the spoon switches under the bumper skirts can get bent, corroded, or broken. If the switches look worn, replacement pop bumper switch and skirt kits are available from Pinball Life. Check the connector at the cabinet-to-playfield junction too — a loose pin or broken crimp in the connector can break the circuit for an entire switch column.
yemons·3/21/2026