The System 80B style sound board will not boot while the auxiliary music board is connected. With the YM2151 pulled from its socket it boots and some sound plays, but the music is missing.

Sound board won't boot with the music board attached: fake YM2151 chip

Cause: The replacement YM2151 sound chip was a counterfeit with an internal short (pin 1 showed continuity to pin 24) that pulled the board down. Recapping did not help.

Checks

• Pull the YM2151 and see whether the board then boots with the music board attached.
• Out of circuit, check the chip for continuity between pins that should not be connected.
• Compare its markings with a known genuine chip; relabelled fakes are common.

Fix

• Fit a YM2151 from a trusted supplier.

Systems

• Gottlieb System 80B

Games

• Night Moves

Related tips

• System 80B sound board LED stays dark until the CPU boots
• Sound boards listed for System 80 to 80B
• The System 80 sound board generations by game number
• Sound board MA-490 main chips
• Sound board MA-766 main chips
• No sound though the sound board boots: 5 V reaching it is low, adjust the trim pot

Source: Pinball Repair help group!! (Facebook group)