5101 RAM speed grades and which MPUs need what

PCD5101P (Philips) is about 150 ns and works on every Bally/Stern MPU. 5101-1, 5101L-1, 5101-2 and 5101L-2 are listed at 450 ns; plain 5101, 5101L, 5101-3 and 5101L-3 at 650 ns; 5101-8 at 800 ns. The Stern M-200 needs 450 ns or faster, Bally -17/-35 boards 650 ns or faster.

Systems

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

Related tips

• Use a fast enough 5101 RAM
• Test EPROM: the least an MPU needs to run it
• Stern games from 1980 on need an M-200 MPU
• Two flashes only: U8 5101 RAM
• Testing an MPU in the game with only J4 connected
• MPU board test points
• MPU board test point voltages
• Why the MPU has ROM jumpers

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