Sega Dreamcast GDEMU 05

Sega Dreamcast repair With GDEMU, PSU and Battery Mod

Just recently my GD-ROM drive stopped reading Discs. It’s time to try something new: GDEMU

Sega Dreamcast GDEMU 01
Sega Dreamcast GDEMU 01

To see if the unit is compatible, the installation instructions recommend to look for a “single digit in a circle, next to the region designation on the back sticker”. Well, there is no digit on this Dreamcast:

Sega Dreamcast GDEMU 02
Sega Dreamcast GDEMU 02

Another way to tell is a stamped “3.3V” on the GD-ROM drive assembly. Guess we are lucky:

Sega Dreamcast GDEMU 03
Sega Dreamcast GDEMU 03

Remove the GD-ROM drive assembly…

Sega Dreamcast GDEMU 04
Sega Dreamcast GDEMU 04

…and insert the GDEMU PCB into the connector:

Sega Dreamcast GDEMU 05
Sega Dreamcast GDEMU 05

Sega Dreamcast GDEMU 06
Sega Dreamcast GDEMU 06

There is a thread in the ASSEMbler board with helpful hints regarding software and compatible memory cards.
It also warns that the Dreamcast will now overheat and crash while playing games. I didn’t experience any crashes but noticed right away that the left side of the unit gets pretty hot. A suggested solution was to direct the air to the fan with a strip of paper.

Sega Dreamcast GDEMU 07
Sega Dreamcast GDEMU 07

Sega Dreamcast GDEMU 08
Sega Dreamcast GDEMU 08

As it still gets very hot there is another possible fix, to disable the 12V rail on the PSU – it seems that PAL units have trouble with the video output after the fix. Since my unit is NTSC/J and has a PAL PSU I followed the directions from this Reddit thread.

Remove the power regulator…

Sega Dreamcast PSU 01
Sega Dreamcast PSU 01

Sega Dreamcast PSU 02
Sega Dreamcast PSU 02

…and the resistor:

Sega Dreamcast PSU 03
Sega Dreamcast PSU 03

Sega Dreamcast PSU 04
Sega Dreamcast PSU 04

Sega Dreamcast PSU 05
Sega Dreamcast PSU 05

While the Dreamcast is disassembled let’s fix the rechargeable battery that died – again. You can use rechargeable coin cells like ML2032 or LIR2032. It’s your choice to go for more expensive cells with solder tabs or regular cells and a three-legged cell holder.
Do NOT use regular CR2032 cells – there is a mod for this though.

Sega Dreamcast Battery 01
Sega Dreamcast Battery 01

Sega Dreamcast Battery 02
Sega Dreamcast Battery 02

Sega Dreamcast Battery 03
Sega Dreamcast Battery 03

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