When I finally fixed my consolized MV1FZS last month and was able to play some games again, I noticed that it outputs mono sound only. It is now time to make some additional modifications to it.
MVS boards need both 5V and 12V voltages, and 12V is used for the audio amp only. As I’m going to add a new stereo audio circuit, there is no need for the 12V feed anymore. This consolized MVS draws the 12V from the now obsolete XL6009E1 DC-DC converter: