Tengugurl
Cheng's Errand Boy
- Joined
- Feb 9, 2017
- Posts
- 111
Hi all!
Learning as I go and loving it!
TL;DR Neo Geo MVS 1FZ is driving me mad! I have replaced 5 ICs and its still not working... Where to next? (Logic probe is in the mail)
1) Got it as a parts console - first booted up with Lower BRAM Error - wouldn't let me get to the other menu via A+B+C+D+ST+SEL. (It initially said: Backup RAM error ADdress 00D000000 Write 5555 Read 0800 but that has since been resolved and now I am stuck with a new error)
2) Replaced the RAM for Upper and Lower RAM with new 62256s (Tried doing it with a donor board first and same issue so I replaced with new)
3) Cool now I was able to boot into the Diagnostic bios menu and see other tests - Oh and lower BRAM error went away but now I have an Upper RAM issue
4) Read a bunch up on: http://smkdan.eludevisibility.org/neo/diag/#causes. (Traced it out and I have perfect connectivity to the C1)
5) Read a bunch on the Wiki page: https://wiki.neogeodev.org/index.php?title=Backup_RAM
6) Watched one of the best Youtubers for Neo Geo anything @GadgetUK+++++ on a similar issue:
7) Replaced U17 from reading this about the 74HC32A https://www.neo-geo.com/forums/index.php?threads/mv-1fz-u17-pinout.235924/ as this was what was needed to fix my Backup RAM error. Still had a Backup RAM error so I replaced IC1 as well from the post above
8) Replaced IC1 as well because for good measure
9) Then read up on a transistor issue on Q1 - replaced that too as I was reading nothing on the transistor when on and or off.
10) Replaced the U7, as well as the schematics, looked as it was part of the flow of the BRAM
11) Looked everywhere for broken traces and measured continuity and I am getting proper continuity
11) Ughghhhhghghghgh I think the only thing that has not been replaced on the BRAM circuit is the C1 at this point but I have connectivity so I am not sure.
Anything else I should try before this thing goes in the bucket of shame till I need my RAM ICs back? haha :P
Learning as I go and loving it!
TL;DR Neo Geo MVS 1FZ is driving me mad! I have replaced 5 ICs and its still not working... Where to next? (Logic probe is in the mail)
1) Got it as a parts console - first booted up with Lower BRAM Error - wouldn't let me get to the other menu via A+B+C+D+ST+SEL. (It initially said: Backup RAM error ADdress 00D000000 Write 5555 Read 0800 but that has since been resolved and now I am stuck with a new error)
2) Replaced the RAM for Upper and Lower RAM with new 62256s (Tried doing it with a donor board first and same issue so I replaced with new)
3) Cool now I was able to boot into the Diagnostic bios menu and see other tests - Oh and lower BRAM error went away but now I have an Upper RAM issue
4) Read a bunch up on: http://smkdan.eludevisibility.org/neo/diag/#causes. (Traced it out and I have perfect connectivity to the C1)
5) Read a bunch on the Wiki page: https://wiki.neogeodev.org/index.php?title=Backup_RAM
6) Watched one of the best Youtubers for Neo Geo anything @GadgetUK+++++ on a similar issue:
8) Replaced IC1 as well because for good measure
9) Then read up on a transistor issue on Q1 - replaced that too as I was reading nothing on the transistor when on and or off.
10) Replaced the U7, as well as the schematics, looked as it was part of the flow of the BRAM
11) Looked everywhere for broken traces and measured continuity and I am getting proper continuity
11) Ughghhhhghghghgh I think the only thing that has not been replaced on the BRAM circuit is the C1 at this point but I have connectivity so I am not sure.
Anything else I should try before this thing goes in the bucket of shame till I need my RAM ICs back? haha :P
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