Dreamcast 12V Rail: Dummy Load Modchip

This little modchip can be used as a dummy load on the SEGA Dreamcast when a GDEMU is installed to prevent the power supply from overheating as the 12V rail isn't used anymore.

When removing your Dreamcast optical drive (GD-ROM) to install an ODE such as the GDEMU, your system now has no draw on the 12V rail which can cause excess heat from the power supply and raise the overall temp inside the shell. This can be even more problematic if you do not use an SD mount to correct airflow or have additional mods inside such as an DCDigital which can also add heat.

There are several options to resolve this such as removing the 12V regulator entirely, but that can break compatibility with certain accessories including RGB Scart cables. This solution simply wires up 3 1K resistors in parallel on a small PCB to help with a lower heat dissipation.

It’s a very simple install requiring only 2 wires (12V and Ground) and can either be installed on the underside of the PSU, or directly on the GDEMU board itself.