A -35 or -17 board in a -133 game will not boot. A -133 board in an earlier game gets damaged.

Game will not boot, or MPU damaged, after swapping -35 and -133 boards

Cause: R113 is a 2K resistor on -17/-35 boards and a diode on -133 boards; with the diode, the 43 V on J4 pin 15 reaches parts meant for a much lower voltage.

Checks

• With the MPU J4 connector unplugged, measure the harness side of J4 pin 15: 6.3 V AC means the game needs a -133 board; 43 V DC means it needs a -17/-35.
• With a -133 fitted and running, MPU TP3 reads about 5 V DC (about 21 V DC on a -35).

Fix

• Fit the board type the game needs, or convert the board (next entries).

Systems

• Bally MPU AS-2518-35

Games

• Baby Pac-Man
• Grand Slam
• Granny and the Gators

Related tips

• Telling a -133 MPU from a -35 or -17
• Converting a -133 MPU to a -35
• Bench-testing a -133 MPU: swap the R113 diode for a resistor
• Convert a -35 MPU to a -133 for Baby Pac-Man and similar games
• -17, -35 and -133 MPU boards compared
• Get the MPU booting before you change any ROM jumpers
• Tell a -35/-133 MPU from a -17 by counting J5 pins
• Jumpers for a -35/-133 MPU running two 2732 EPROMs (U2 and U6)

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