Test a leaf switch diode in place

Steps

• Leave all wires and the diode connected and the switch open.
• Diode test with black on the band and red on the other end: about 0.4 to 0.6 V.
• Reverse the probes: no reading.

Systems

• Data East CPU Version 1/2
• Data East CPU Version 3
• Data East/Sega CPU Version 3b

Related tips

• What a bad switch diode does
• Test a switch diode (fail-safe method)
• Test the switch column drivers with a diode jumper
• Test the switch row inputs with a diode jumper
• Which switches are outside the switch matrix
• Use a real ball in the switch test
• Cleaning leaf switch contacts
• Clearing a switch from the power-on switch report

Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part Three, Clay Harrell (pinrepair.com)