Bench testing a rebuilt rectifier board

Steps

• Clip a line cord to rectifier J2 pins 6 and 7 with two alligator leads.
• Put the meter's black lead on the R1 or R2 lead nearest the fuses (R1 right-hand lead on a -54).
• Plug in and read the test points. Unloaded, expect about TP1 6.4 V (-18) or 8.2 V (-49), TP2 195 V (as low as 150 V), TP3 13.5 V, TP4 7.5 V AC and TP5 47 V.
• If readings are far off, recheck the work and R1 (600 ohm) and R2 (25 ohm).
• Then refit the supply in the game with only J2 connected and check again before plugging in J1 and J3.

Line voltage (120 V AC) is present on the rectifier board and its J2 connector; unplug the game before touching it. The score display supply runs at 170-230 V DC; keep hands off the rectifier and driver boards with power on.

Systems

• Bally MPU AS-2518-17
• Bally MPU AS-2518-35
• Stern MPU-100
• Stern MPU-200

Related tips

• What each rectifier on the board feeds
• Rectifier board test point voltages
• The three Bally rectifier boards
• Rectifier test point ranges with fuse and rectifier
• Where the 43 V solenoid supply leaves the rectifier board
• No +12 V at rectifier board TP3
• Random reboots during play: reflow the rectifier board
• Rectifier test point reads below its range

Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part One, Clay Harrell (pinrepair.com)