The long flash appears but the single short flash for the 5101 RAM does not.

Test EPROM stalls before the RAM pass flash

Cause: Bad 5101, broken traces between it and the 6502, a damaged 6502 R/W line, or faulty select chips Z4 and Z36.

Checks

• Check the 5101 and its traces.
• Check for the 3K pull-up on the 6502 R/W line; early boards lack it.
• Check Z4 and Z36.

Fix

• Replace the failed chip, repair traces, and add the R/W pull-up if missing.

Systems

• Gottlieb System 80
• Gottlieb System 80A
• Gottlieb System 80B

Related tips

• Test EPROM stalls at the switch matrix RIOT (U4)
• Test EPROM 2: game PROM socket test fails
• Test EPROM stalls at the display or lamp/solenoid RIOT
• System 80 test EPROM LED flash codes
• Replacing U2 and U3 with one 2764 EPROM
• Ways to fit EPROMs at U2/U3
• Which System 80 test EPROM image to use
• Bench setup for the System 80 test EPROM

Source: Gottlieb System 80 Test EPROM V3.2 (February 2015), Pinitech