PS One Modchip original game problem

I Chipped dozens of the original Playstations back in the day and never came across this, I chipped the PSOne with the onechip. Everything seemed to work fine, booted several backups and they loaded, so today I came to play R-Type Delta the original game and there seems to be some audio missing. The heartbeat sound wasn't there when the game starts. Has anyone any idea what could be causing this? Apart from that the game seems to be working.

 

^^ that's either a modchip fault or a lens issue?
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please post image of pcb setup!
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this has happened to others because they didn't wire it right, it's as if they set the console up to trade retail playback for backups...
turned out, it was the modchip! (never encountered where the lens took a shit bang on that coincidence, they removed modchip and restored console functions)
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i'm leaning on modchip setup...but the lens, the lens...
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[edit]
same for audio issues on a single retail out of hundreds they have that worked before, but not on the mod job...

 

If sound is missing in the FMW and in the XA audio, seems you have using a copy with 2024 byte\sec...
Very strange if you say that are an original game :\
Post pics of the mod, but I barely think that's the culpit...