You don’t need no stinkin’ boombox to play Mega Drive games, just a suitable regulated 5 V power supply. My test supply was rated for 2 A on the 5 V rail, but that is the current it can provide, not current it forces into the Game Unit.

So you’ve got an Aiwa Mega-CD and you want to make sure your Game Unit attachment is working well? Good news, the Mega Drive section can be powered independently of the Aiwa Mega-CD boom box with a suitable regulated 5 V supply.

First up you need a power source. I had an old LaCie ACML-51 external CD-ROM power brick hanging around so I gave it a go. It provides an ample 2 amps (Ha!) on the 5 V rail and we won’t be using the 12 V rail for this one, unless we want a fire… ;) Check with a multimeter to make sure your power adapter is outputting close to 5 V.

Here we have ground connected to pin 12 and 5 V (white) connected to pin 24 on the unit I tested, using the numbering shown in the photograph. The red 12 V lead was left unused. Before applying power, verify the pin numbering, polarity and voltage with a multimeter, and insulate the unused lead and exposed connections so they cannot short. Connect your AV cable, insert a cartridge and then power up and sit tight.

If you inserted a cartridge, you’ll see a familiar SEGA splash screen or…

…the very start of the Sega Mega-CD intro if you didn’t insert a cartridge. With no link to the boombox’s CD-ROM hardware in this setup, the intro starts but then hangs.

Sources