GDEMU installation

All you will need to install GDEMU is one PH#2 screwdriver.

Before you start:
Make sure your Dreamcast is VA1 model. The best way would be to disassemble it and read the description on the mainboard, next to pad ports. Another good method is to check the single digit in a circle, next to the region designation on the back sticker:

DC PAL VA1 back

If it says “1”, you have a VA1 model. You can further confirm that after removing the upper cover, the GD-ROM drive assembly should be stamped with “3.3V”.

Installation instructions:
Text-only for now, pictures will be added later. Please follow the steps outlined below, do not use force – especially when plugging GDEMU into Dreamcast motherboard – to avoid any damage.

  • Disconnect all cables from the console
  • Remove disc from drive and close the lid
  • Detach modem add-on, place the console upside-down on a firm surface
  • Remove 4 screws located in the corners using a Phillips PH#2 screwdriver
  • Hold the console by sides with both hands and carefully rotate it to upright position

IMPORTANT: Make sure the now unscrewed upper cover does not fall down. It holds down part of the GD-ROM drive assembly, which might became separated and pull/damage the ribbon cable.

  • Lift Dreamcast’s upper cover and place it aside
  • Remove 3 screws holding down GD-ROM drive
  • Gently pull the drive up to separate it from the mainboard, then store it away

IMPORTANT: Do not twist, it takes only as much force as a typical HDMI connector to remove the GD-ROM drive. Keep the drive assembly upright at all times. Store it in a clean plastic bag, perhaps bubble-wrapped to provide extra protection.

  • Insert GDEMU in place of the drive, use your fingertips to make sure the socket is aligned properly before you try to push it down

2014-05-29 update for GDEMU models with screw mount:

These models come with 3×20 metric screw with Pozidriv PZ1 head, its thread might not fit the hole perfectly and thus be somewhat difficult to install. You can replace it with a non-metric screw provided it has exactly the same dimensions.

GDEMU v5.1
IMPORTANT: Do not replace provided screw with a longer one. Do not attempt to install the screw without PCB and sleeve in place. Otherwise the screw might go deep enough to reach and damage the console mainboard.

A simple way to make sure the sleeve aligns properly with the hole and stays that way:

  • Put the sleeve standing over the screw hole, make sure it’s well centered
  • Hover GDEMU over the mounting area, align the PCB hole with the sleeve before you gently put it down, and do not push the connector in yet
  • Drop the screw into the hole in PCB to make sure the sleeve won’t move away
  • Now push the GDEMU down to sit it properly, and then finish by screwing it down

GDEMU v5.1 - inside DC

That’s it, you’re now good to go. Do not turn Dreamcast upside-down with GDEMU inserted if it’s not being held down by screw. I strongly suggest to put the upper cover back to avoid electric shock and/or injury, or damage to console internals or GDEMU. No need to screw it back on though. Modem add-on can be now plugged back in if you wish. Read Operation.

External buttons:
You can solder wires to extra buttons (to be mounted directly in the case, for example) by yourself. See the figure below:

GDEMU v5 extra buttons

From left to right: GND (common ground), DOWN input, UP input. You can solder both, or just one of them. Connect the buttons to GND on one end and chosen input on the other.

IMPORTANT: Certain early v5 PCBs will have a wire on the back soldered to UP input. You can still use this solder point for your own wires, just make sure not to desolder that original one or else the button on the PCB will stop working.

Remote:
If you got remote PCB with your GDEMU you will need to assemble it yourself. The choice of having only LEDs there, or only buttons, or both, is up to you. Part list:

  • 2x TACT button, NO/ST
  • 4x 330 ohm 0603 resistor
  • 4x 1206 LED

You can use any LEDs you like but keep in mind that blue, white, and some of the bright greens require about 2.5V to work. The resistors will need to be smaller value, though due to being brighter in general even 330 will do fine. Typical red, yellow and green LEDs need 1.5-1.7 volts. If you do change resistors make sure to limit the current to sane values – 1-5mA. 10mA if you really want super bright.

LEDs are arranged in common-anode setup. Use the 3.3V line provided by GDEMU to power them. If in doubt (the markings can be sometimes confusing), solder one down and see if it works🙂

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