Dreamcast battery replacement mod (2xAAA)
I recently got a Dreamcast to play some of the unique games on the console (mainly Seaman and Samba De Amigo) and quickly noticed that the internal battery was drained which would cause the internal clock to reset every time I powered the console off. To play certain games (including Seaman) your clock needs to be fully working, so I set out to find a replacement.
Finding information about how to replace it seemed to be simple enough, but many people seem to disagree on what kind of battery is actually in there, some claimed it to be a normal CR2032, the ones in the VMU; others claimed it was a rechargeable version, the ML2032. When I opened mine up it turned out to be a ML2430 (datasheet) which seems roughly equivalent to the ML2032. A problem is that these batteries are insanely expensive, and I’m not even sure they’re being manufactured anymore. However, we can use two cheap rechargeable AAA batteries for the same effect.
Disassembling the Dreamcast
Snesorama.us member shredhead posted a simple tutorial, all credits to him, I’m just adding my additional pictures and experience. If you’re looking for the long version, go ahead and read the linked post.
You start out by disassembling your Dreamcast. There are four screws on the back and when they’re out the top slips right off. You’ll have something looking like this (click image for larger version):
First, you need to unscrew the power supply unit (the left circuit in the picture) and lift it out. It usually sits pretty tight, so be firm but careful. It’s attached with six pins (‘A1’ in the image) which you need to be careful not to break when you pull it. It will still be attached to the power button, so you can just leave it hanging on the side.
Then unscrew the controller ports module, detach the ribbon cable carefully (‘B’ and ‘B1’, respectively) and lift out the module. Also note the battery at ‘C’.
Now things should be looking like the image below.
Now that we have the controller module, let’s get started on assembling the battery pack. Wire the two rechargeable AAA batteries according to the guide below.
“Crap wiring guide”, kindly borrowed from the original post below:
Here’s how my pack turned out. first soldered and then bundled together with electrical tape:
Soldering on batteries isn’t the easiest of things, so I’d recommend buying special batteries suitable for soldering. (usually available in well-stocked hardware stores) but they might end up costing you as much as a replacement battery, so if you’re handy and quick with the soldering iron you’ll probably manage it just fine. Remember not to expose the batteries to the heat of the soldering iron for a prolonged time, as this can decrease the voltage you get out of them. Mine went down from about 2.5v to just below 2v (tested with multimeter.) but everything still works just fine.
Assembling the battery pack and controller.
Note the picture of the controller board upside down, it shows the polarities that you will need to connect. You will only need to solder one of the positive connectors. You will need to remove the old battery first by applying your soldering iron to the three points while wiggling the battery until it comes loose.
Finished result after soldering and assembling everything again:
(Yes, I screwed up the cable colors, the black one is positive and the yellow one is negative!)
The pack fits snuggly between the GDROM drive and the ribbon cable, I used another piece of electrical tape to make sure it sticks.
Best of luck with this mod, may it give you a reason to dust off your Dreamcast!