MPU VR1 is an 8.2 V zener; the manual's "1N9598" is a misprint
VR1 in the MPU reset circuit is an 8.2 V zener: 1N959B (1/2 W) or 1N4738A (1 W). The Bally manual prints it as "1N9598", which is the same part mislabeled.
Systems
Related tips
- Garbage in the bookkeeping totals
- MPU boots only some of the time
- MPU LED locked on with no flicker: likely causes
- What the MPU VR1 zener does
- Single reset parts that hold the LED on
- Testing an MPU in the game with only J4 connected
- MPU board test points
- MPU board test point voltages
Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Two, Clay Harrell (pinrepair.com)