The Simpsons Repair Logs

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Repairer: channelmaniac

Symptom: Will not boot. Bad ROM error

Board had attempted upgrade and repair damage. Many plated through holes and traces were damaged on the sound ROM and around the sound ROM.

Replaced 2 bad sockets and patched 10 traces. Board would then boot but was stuck in a reboot cycle when trying to test the ROM in location 15C on startup. Reset only happened when the board was first powered on after sitting. Custom IC 051550 was resetting the system. Soldered JP1 to disable the watchdog to finish the repair.


Symptom: Stuck in reset (Watchdog)

The data bus lines were stuck high. Checked the 74LS245 at 12D. It was good. Pin 22 at 13C and 15C should've mirrored pin 22 at 16C/17C but was stuck high. Repaired broken trace between 3F pin 8 and pin 22 of 13C/15C. Tested game.



Symptom: Plays blind - random garbage on screen.

Board would sometimes work perfectly then on next power up be scrambled again. Resoldered damaged pins on 053247 at 7J and repaired 1 shorted trace where a solder pad was mashed into a neighboring trace. This helped but did not fix it. Replaced missing 051550 hybrid IC and tested. Board worked except was missing sounds 01 through 28. Found a factory solder bridge between pins 23 and 24 of 053260 at 3E. Removed the bridge and all the sounds are now working. Ran self tests and found the P4 down control stuck low. Replaced a bad 005273 hybrid module at S37 to fix. Played the game all the way through to check it out.