An interesting and unique issue with some revisions of PCE/TG-16 games has been found, as well as a potential fix! It started (as with many things in life) by an accidental discovery…
Tianfeng was testing Artemio’s upcoming version of MDFourier for the PCE and noticed that some games would have bad noise in parts of the game that were supposed to be silent. As first (as with most of us hardware nerds), he assumed it was hardware-related: Was it the HU Card? The version of PCE hardware? Cables???
He tested multiple games on his everdrive and found that some had the issues and some didn’t. Artemio then checked on multiple emulators and found that some of them did not have this issue. After some further digging Artemio discovered that some games were essentially panning stereo, rather than turning down both sliders and this could be linked to a certain register in the games code.
The fix was tested on a few games so far and theoretically be used to patch any game with a similar audio bug. More information, as well as a potential fix for affected games can be found here: http://junkerhq.net/pcenoise/
…and now we all have one more excuse to use our ROM carts over original games ;p