Reset capacitor workaround for boot garbage

Steps

• This only masks the fault; look for the real cause first.
• Fit a 0.1 uF 50 V ceramic capacitor between CPU U1 pin 40 (reset) and ground.
• Without soldering on the board: crimp or solder two female .093 in Molex pins to the cap leads, sleeve the leads with heat shrink, and plug it into P7 pin 1 (reset) and pin 23 (ground), the first and last pins of the top row.
• Fold the capacitor over the plug out of harm's way. Results vary: it may cure the problem fully, partly or not at all.

Systems

• Gottlieb System 3

Related tips

• CPU board will not boot, or keeps rebooting
• Nonsense message at boot, game stuck in a loop
• Reading the CPU board LED
• Booting a CPU board on the bench
• CPU board LED never lights
• Logic chips worth stocking
• U11 must be a 74HC123AN
• Replace a failed 6116 RAM with a 6264

Source: Repairing Gottlieb System 3 Electronic Pinball Games from 1989 to 1996, Clay Harrell (pinrepair.com)