A few years ago, I bought a Super Game Boy on eBay. Certain sounds appeared to work, like hitting the L+R Buttons to bring up the menu, worked with no problem. But the games I played had no music or sounds!
Luckily, I found a forum that proposed an answer. I don’t have the electronics expertise to verify this myself (I only recently found someone who may attempt the fix for me), but several of the comments confirmed this to be a known issue and this was the correct solution! After a recent attempt to revisit the old forum, it turns out the domain has expired. I have posted the text of the solution in other places, but I wanted to archive the text as well as the image that was originally provided in the forum. See below for the fix!
click to enlarge
The author’s instructions indicate you should replace the two caps near each other with “4.7 25V” caps – and if you have a graphic glitching issues, you can replace the 3rd capacitor (just above pin 58) with a “22 6.3V” capacitor.