Replacing the 78H05 +5 V regulator

The +5 V regulator is a TO-3 78H05 (up to 5 A) on the big black heat sink, and it is hard to find. The author planned to try the pin-compatible TO-3 LM323K (3 A) used on the 1977-1985 Bally supplies, reasoning that the 6803 system draws less power.

Systems

• Bally 6803

Related tips

• WPC power driver bridge rectifiers and +5 V regulator
• Resets: +5 V at the driver board test point is low
• Resets remain after rectifiers, caps and connectors are done
• Power supply test points and their voltages
• No +5 V at TP1 or no 14 V at TP5
• No 43 V for the coils
• Power supply test point ranges
• Strange intermittent faults from power supply solder joints

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