Power supply test points and their voltages

TP10 is ground (bottom left). TP1 +5 VDC (top right); TP2 170-190 VDC display output, set by VR1; TP3 about 230 VDC display input; TP4 43 VDC coil power (top left); TP5 about 14 VDC unregulated logic supply; TP6 and TP7 11 VAC lamp phases; TP8 and TP9 6.3 VAC GI.

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

• Power supply test point ranges
• Strange intermittent faults from power supply solder joints
• No 43 V for the coils
• Replacing the 78H05 +5 V regulator
• Bad +5 V bridge diodes D1-D4
• +5 V still bad with good C1 and diodes
• 6803 power supply fuse ratings
• Rebuild the high-voltage display supply

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