I have a Japanese Soccer Brawl home cart.
The game plays perfectly.
Insert: Damaged on the top right (see picture), slightly wrinkled on top
Box: No cracks inside, the plastic is in good condition and tight. (no wrinkles)
Cart: Insertion marks and some scratches on the front.
I once opened a Japanese bootlegged AES Twinkle with flash roms in it (fitted on adapters). It weighted exactly the same as the regular cart (maybe it was a few grams off but the difference was hardly noticeable.)
The game was sold as an original and came with offset an printed manual/sticker...
Did you try to resolder the flash roms ?
The only roms that should be reprogrammed if the sound doesnt work is the m1 and v1 (m1 if there is no sound at all, v1 if the sound is garbled).
But i doubt the v1 would have been corrupted if its since its electrically erasable only.
Maybe I can help a...
How is the sound corrupted ? is it scrambled ? only the sfx ?
I'm surprised to see a 26L6420 for the V, cause it's a 16bit rom, and V roms have to be 8bit usualy, but I'm no expert.
Check for dry solder joints around the 26L6420 on the prog board (maybe just put some flux on it and refresh the...