Due to a conversation on the wiki, we've got a few questions of anyone with a Famicom, an MMC5 game, and the ability to investigate (any of soldering iron, multimeter, sound pressure meter, oscilloscope, whatever).
A few games—as far as I can tell, all of the ones that actually use the MMC5's audio capability—use a different sized resistor somewhere in the audio path. Without an actual cartridge in a Famicom, it's hard to figure out what's going on.
So:
A few games—as far as I can tell, all of the ones that actually use the MMC5's audio capability—use a different sized resistor somewhere in the audio path. Without an actual cartridge in a Famicom, it's hard to figure out what's going on.
So:
- Would someone with access to an HVC-ExROM cartridge be willing to trace the audio path? Unlike the vast majority of other cartridges, it's complex enough I can't do so solely from photos.
- Can anyone record or measure the difference in volume when R2 is changed from 15kΩ to 6.8kΩ? Merely swapping between games is probably not enough, because as far as I can tell, no games ever used the MMC5 audio with the 15kΩ resistor present. But a TNS-HFC3 might work (depending on the audio circuit topology)
- Has anyone established why the MMC5 had four separate pins for expansion audio? Do we know what all four pins do?