TP2 reads above 190 VDC and turning VR1 does not bring it down; displays may be dim, dead or damaged.

Display high voltage above 190 V and VR1 cannot lower it

Cause: The high-voltage regulator section has failed, usually its transistors.

Checks

• Measure TP2 to TP10 with the game on.

Fix

• Replace Q1 (2N3584) and Q2 and Q3 (2N3440, Q3 on a heat sink); see the full high-voltage rebuild list.

The display supply runs at 170-230 volts DC; touch nothing on the high-voltage section with the game on, and let it discharge before working on it.

Systems

• Bally 6803

Related tips

• Score displays dead or dim: high-voltage section parts
• Turn the display voltage down to 170 V
• Rebuild the high-voltage display supply
• Replace high-voltage caps C6 and C7 before they take out Q2/Q3
• Strange intermittent faults from power supply solder joints
• Power supply test points and their voltages
• No 43 V for the coils
• Where the boards sit in a 6803 backbox

Source: Repairing Bally 6803 Pinball Games from 1985 to 1989, Clay Harrell (pinrepair.com)