A missing test point voltage: what to check first

Every Bally board has labelled test points, and readings within 10% of nominal are fine. When one is missing, look first at the fuse, the connector and the board header pins before suspecting other parts.

Systems

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

Related tips

• MPU LED lit solid: check +5 V first
• First checks for any missing voltage
• MPU board test point voltages
• Solenoid driver TP1 below 5 V with TP5 normal
• No +12 V at the MPU: check the rectifier board
• Route of the +12 V supply to the MPU and 5 V regulator
• MPU locks with LED on because of C23 or Q20 on the solenoid driver board
• Rectifier board test point voltages

Source: Voltage Test Points on the Boards