Quick diode test of a bottom-panel bridge rectifier

Steps

• With power off, set the meter to diode test.
• Red lead on the ground lug (the one with the green wire); black lead on each of the two neighbouring lugs in turn: expect 0.4 to 0.6.
• Black lead on the positive lug (diagonal from ground; on newer bridges it is turned 90 degrees); red lead on each neighbouring lug in turn: expect 0.4 to 0.6.
• Any reading outside that range means the bridge is bad; replace it with a 35 A 400 V lug-type bridge.

Systems

• Gottlieb System 80
• Gottlieb System 80A
• Gottlieb System 80B

Related tips

• Identifying the leads of a bottom-panel bridge rectifier
• Bottom-panel bridge rectifiers and fuses
• Check the 80B bottom-cabinet 10,000 mfd filter capacitor
• System 80 games have no surge protection on the line input
• What the two System 80 transformers supply
• Telling the logic filter cap from the coil filter cap
• First power-up, step 1: check the bottom-panel fuses
• A bottom-panel fuse blows the moment the game is switched on

Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part One, Clay Harrell (pinrepair.com)