Fit new C14 and C15 for a cleaner reset and clock

The two 470 pF capacitors C14 and C15 weaken with age, giving a softer signal on a scope. Replacing them is cheap and worth doing during an MPU rebuild.

Systems

• Bally MPU AS-2518-17
• Bally MPU AS-2518-35
• Stern MPU-100
• Stern MPU-200

Related tips

• No clock at the CPU: U15, U16, C14/C15
• Building a replacement SRC pack from discrete parts
• MPU reset section parts by position
• M-200 clock-speed jumpers E32-E33 and E34-E35
• Stern M-200 occasionally will not boot and the MPU reset button does nothing
• MPU board test point voltages
• MPU stops before the 7th LED flash (no 43 V)
• Add a ground jumper on every -17/-35 MPU

Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Two, Clay Harrell (pinrepair.com)