The Totem-and-later sound board goes silent or acts up; logic chips or the 6530 RIOT fail.

Second sound board chips dying from a bad ground

Cause: The board grounds through two zinc-plated mounting screws that corrode. With an intermittent ground the on-board 7805 output can rise to about 12 V and destroy chips, including the unobtainable 6530.

Checks

• Inspect the mounting screws and the 7805 mounting hardware for corrosion.

Fix

• Fit new, clean mounting screws.
• Clean the 7805 hardware and add a little grease to keep moisture out.

Systems

• Gottlieb System 1

Related tips

• System 1 sound: chimes and two sound boards
• Replacing a sound board with a chime box
• What boards a System 1 game has

Source: Gottlieb System 1 Pinball Repair from 1977 to 1980, Clay Harrell (pinrepair.com)