Difference between revisions of "PCB Repair Logs The Simpsons"
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'''Diagnosis:''' Noticed that when going into the self test and doing a ROM Check the two mask ROMs for the samples at 1D and 1F were never being tested – the test seemed to skip those, so it tested the rest of the ROMs and put up ‘OK’ with a checksum, but never put up a checksum for 1D and 1F or even an ‘OK’. <br> | '''Diagnosis:''' Noticed that when going into the self test and doing a ROM Check the two mask ROMs for the samples at 1D and 1F were never being tested – the test seemed to skip those, so it tested the rest of the ROMs and put up ‘OK’ with a checksum, but never put up a checksum for 1D and 1F or even an ‘OK’. <br> | ||
Played the game and checked the schematics and found no address or data line activity on those ROMs. The addressing comes from the surface mount Konami custom ‘053260’ at location 3E and the inputs to this chip were good, just no output. So had to replace the chip with one from another Konami board of that era, then the sound worked perfectly. | Played the game and checked the schematics and found no address or data line activity on those ROMs. The addressing comes from the surface mount Konami custom ‘053260’ at location 3E and the inputs to this chip were good, just no output. So had to replace the chip with one from another Konami board of that era, then the sound worked perfectly.<br> | ||
<br>'''Cure:''' Replaced faulty ‘053260’ Konami custom chip at location 3E<br> | <br>'''Cure:''' Replaced faulty ‘053260’ Konami custom chip at location 3E<br> | ||
<br>[[PCB_Repair_Index|Back to PCB Repair Index]] | <br>[[PCB_Repair_Index|Back to PCB Repair Index]] | ||
Revision as of 10:39, 21 August 2012
The Simpsons
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| PCB Image | Reserved |
|---|---|
| Pin Out | Reserved |
Repairer: VectorGlow
Forum Thread: The Simpsons PCB Repair
Symptom: No sound, but sound amp okay
Diagnosis: Noticed that when going into the self test and doing a ROM Check the two mask ROMs for the samples at 1D and 1F were never being tested – the test seemed to skip those, so it tested the rest of the ROMs and put up ‘OK’ with a checksum, but never put up a checksum for 1D and 1F or even an ‘OK’.
Played the game and checked the schematics and found no address or data line activity on those ROMs. The addressing comes from the surface mount Konami custom ‘053260’ at location 3E and the inputs to this chip were good, just no output. So had to replace the chip with one from another Konami board of that era, then the sound worked perfectly.
Cure: Replaced faulty ‘053260’ Konami custom chip at location 3E
