Video Game Collecting

Hands down it seems the best place to get any retro game hardware is the thrift store.  In 7 days time I’ve witnessed a $3 Model 1 SEGA Genesis (with no cables), and then just yesterday at the same thrift store I found a $15 Model 1 SEGA Genesis with all of the trimmings (two licensed three button controllers, RFU adaptor, and licensed AC adaptor).  It seems those AC adaptors are becoming more and more difficult to find, and used game stores don’t seem to be aware that the original model Genesis is not compatible with the 2nd and 3rd generation adaptor.  Some even think an original Nintendo NES AC adaptor will work because it fits and its the same voltage, but this couldn’t be further from the truth. 

You see the Nintendo AC adaptor spits out its power as AC and converts it to DC inside the Nintendo itself.  The Genesis requires the voltage to be DC.  A lot of the games stores assume it works when they turn it on because the light on the SEGA Genesis comes on.  But the reason why it turns on is because of the alternating current.  That red light is an LED (light emitting diode).  It will only turn on if voltage is flowing in one direction (DC).  If an LED is connected to a power source incorrectly it will not turn on.  When its connected to an AC powersource it will turn on regardless of which wire is connected to which lead.  The alternating current occurs so fast that the light appears to remain solid, when infact its actually turning on and off super fast.

With four diodes you can actually convert that AC current into DC, and theoretically the AC adaptor should work.  The diagram below kinda demonstrates that.  The red light indicates the + and the black indicates the -.  Notice how the current alternates (red to black then black to red) the terminals on the right stay their same color (and therefore their same polarity).  The diodes that turn gray are indicitive of the voltage being blocked.

So it might be possible with just four simple and cheap diodes make an adaptor (or a permanent modification) to an existing NES AC adaptor and convert it into one that is compatible with a SEGA Genesis.  Sounds like a weekend project for sure.