Testing the time expander flasher (under the red dome) lights three playfield lamps instead of the flasher, even though flashers are not part of the lamp matrix. Swapping the CPU board, driver board and ribbon cable makes no difference.

Flasher test lights playfield lamps instead: miswired mini-playfield harness

Cause: A previous owner had spliced wiring at the mini-playfield harness connectors incorrectly (a lamp wire joined to a flasher wire), and one wire was left disconnected.

Checks

• Compare the mini-playfield harness wire colours with the manual's inter-board and playfield wiring pages.
• Look for splices or hacked connectors where the mini-playfield harness joins the main harness.

Fix

• Undo the incorrect splices and restore the original wire-to-wire connections at the mini-playfield connectors.

Systems

• WPC Fliptronics

Games

• Doctor Who

Related tips

• Lamp matrix connectors on the driver board
• Phantom switch closure that survives a new CPU board: bad 4N25 on the driver board

Source: Pinball Repair help group!! (Facebook group)