Were I live now, I'm fortunate to have what I'm beginning to assume is a shop of a dying breed: the independent video game store. This seems especially true now that GameStop owns pretty much every other game store chain. While poking my head into the one closest to me, I uncovered a little gem from my youth: , the resulting nostalgia bomb was irresistible, but now I needed a console to play on, I haven't owned a Sega Genesis since I regrettably gave mine away to a relative years ago.
While the little shop did have a Genesis in stock (and even a 32x to go with it), this thing caught my eye. The Retron 3 is a clone system that can play NES, SNES, and Genesis games, just the thing for a retrogamer who is running out of A/V inputs on his TV (and it was on sale!). I took the little thing home, with a Sega controller (good, because the "wireless" controllers that came with it were pretty awful) and was shortly afterwards playing a cyborg kick-boxer punching a caveman in the face, awesome.
The system seemed to work great, for my NES and Sega collections, but things went sour when I tried out one of my few SNES carts; the sound was horribly distorted as can be heard here. It sounds like some serious clipping, like the volume was cranked up too high. Turns out I was right, this was exactly the case: a little more research revealed a flaw with the assembly of the unit's SNES side. For the SNES's audio amp, they used 2.7kOhm resistors, when something like 33kOhm would have been appropriate. Perhaps this was a typo on the data sheet or similar because the resistors in question are SMD, the don't have the traditional color bands a 2.7K Ohm resister is simply marked '272' where as a closer 27k Ohm would be marked '273'. Enough of the electronic lesson, it's clear that the solution is to crack the beast open and give it a transplant.
This seemed like a fantastic
opportunity excuse to use my fancy new tool toy : SainSmart DSO203 Nano I'd wanted an oscilloscope for a long time, but being at best a hobbyist, could never justify having a full expensive bench unit. This little beauty is smaller than my cellphone, and let me trace the audio signal to the spot on the board. (In theory anyway, I was pretty new at using an oscilloscope.)
Special thanks to Benheck.com user Ace_1, who seems to be the resident expert on clone systems, for pointing me in the right direction as to which resistors to replace, as I'm still a rookie to using an oscilloscope, it was taking me a while to trace the audio out on the board.