Testing the diodes on a flipper coil

Steps

• Cut one lead of each diode free from the coil lug.
• Meter on diode test: black lead on the banded end should read about 0.4-0.6 (about 0.5).
• Reverse the leads: no reading.
• Resolder the lead, or fit a new 1N4004.

Systems

• WPC Alpha-Numeric
• WPC Dot Matrix
• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)
• WPC-95

Related tips

• Resets from damaged flipper coil diodes
• Testing a coil diode
• Testing the diode on a coil
• Which way a coil diode goes
• Which way a coil diode goes
• Testing a coil, switch or flipper diode with a meter
• What the coil diode does and how a bad one shows up
• Testing a coil diode on the driver board

Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part Two, Clay Harrell (pinrepair.com)