This tutorial is for the GDEMU Dreamcast


 What is the GDEMU ?

GDEmu is a GD-ROM emulator for our Sega Dreamcast
Here is the link to the official site:

Temperature problem after installing the GDEMU?

Many people talk about heat and high temperature in their dreamcast after installing the GDEMU.
Indeed, the 12V power rail dedicated to powering the optics / spindle displacement motors is no longer useful.
In the absence of load on the rail the output voltage of the regulator reaches 14V This voltage is responsible for the temperature rise of the regulator.

Yes, but what to do ?

A first solution was found: "remove the 12V regulator". It is a mistake!
The 12v is also used to switch the TV to RGB.

A second tip has arrived: charge the 12V circuit using a 330 Ohm resistor in the power connector.

The idea is good, but only one resistance is a bit tight, it will very quickly turn into a radiator It too ...

An evolution of this modification has been found, dissipating the heat on 3 resistors of 1K ohms mounted in bypass.
After calculation it gives 333 Ohms.
This modification is the best to date.

The problem is the GDEMU !

Everyone tackles the power part of the dreamcast to add these resistors in the power connector, but the problem does not come from the power, the problem is not taking into account the 12V load by the GDEMU !
It is therefore necessary to modify the GDEMU itself, it becomes by this principle plug and play, and the dreamcast remains intact.
Looking at the electrical diagram of the dreamcast, we see that the 12V is redirected to pins 25 of the connector CN503 which is the connector of the GD-ROM, either the connector or plug in our GDEMU.


The modification consists in adding 3 resistors of 1K Ohms of 1/4 watt directly on the GDEMU. After a quick analysis, the welding points are found:

Mod done !

Enjoy it !