Gary Judge

I was originally inspired by this video which seems to be one of the very few examples (which I could find at least) of a circuit bent Master System:

However there appears to be almost no instruction on how to re-create these effects so I starting pulling apart a Master System II to see what I could find out. My initial attempts at trying to circuit bend the game ROM were very disappointing. I only seemed to be able to get the system to crash and not do much more – even with resistors. I therefore took the approach of having a go at the graphics chip…This was harder to find than I had thought. However once I had identified the Sega 315-5246 as the graphics chip, things started falling into place.

The SMS Power! forum has provided lots of useful info about the Master System including a pinout diagram of the graphics chip which helped me to focus which pins to short circuit:

http://www.smspower.org/forums/viewtopic.php?p=46388

I seem to be getting much better results now. Sonic the Hedgehog (on board game) is producing some nice graphical glitches without locking up the machine.

My next task it to hard wire up some of the pins and introduce potentiometers in an attempt to regulate the amount of glitch. Once I have something up and running I will produce a more detailed explanation of what I have done and why and possibly attempt a video / screen shots of the new and improved unit in action.