Finally got around to working on my SF. The game had heavy acid damage on the CPU when I bought it so I purchased a NOS replacement board. I installed the board and after cleaning and reassembling the playfield played a few games. There were no issues until the game locked up about 15 minutes in. A reboot at this point shows 8 flashes on the board instead of 9. The 9th flash: "verifies operation of the Phase A switched ill. voltage. Note: F4 fuse on the power module provides the phase A signal to the control board. (U1, 6803) (U11, 4011) (U12, 14584)". The F4 fuse is correct according to the manual. Once it cools off you get the normal 9 flashes and it plays fine until 15 minutes or so goes by. Then it locks up again. What should I be looking at?

Steve

#2 10 years ago

CHA

Steve-in-CT

Pinside member

Killingly, CT

12y 43,650 283 10

No help out there?

#3 10 years ago

CHA

Steve-in-CT

Pinside member

Killingly, CT

12y 43,650 283 10

Almost 24 hours with no replies. I'm losing my faith in Pinside.

#4 10 years ago

CHA

Steve-in-CT

Pinside member

Killingly, CT

12y 43,650 283 10

#5 10 years ago

AMS

barakandl

nvram.weebly.com

12y 132K 10,417

Before messing with the boards, verify power connectors. Not too familiar with 6803, but they must use the switch illumination crossing zero to time things. Maybe the connector pin going to the MPU is cracked. Or perharps the connector pin leaving power board is cracked.

Could try clipping a meter lead on the MPU test point for that switched illimination voltage it uses and see if drops out when the game locks up. That will help narrow down your focus.

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