Dreamcast Controller Board Fix

The SEGA Dreamcast suffers from a really common problem that causes the controllers to stop functioning. This is normally triggered if you have a controller with a loose wire or if you repeatedly unplug/replug controllers while the Dreamcast is powered on.

The root cause of the problem is a blown fuse (labelled F1) on the controller board, the fuse is probably underrated as many people have had no further trouble after bypassing it entirely. However, bypassing the fuse does risk damage to other parts of the Dreamcast if there is a sizeable power surge so this isn't an ideal fix.

The Internet is full of terrible hacky fixes for this issue including:

• Replacing the fuse with a 10 Ohm resistor (wat?!)
• Twisting the fuse legs together to bypass the blown fuse
• Adding two resistors in parallel (double wat?!)
• Replacing the normally totally unrelated 13 Ohm R1 resistor as well the F1 fuse with 10 Ohm resistors

All of these fixes are wrong. Bypassing a fuse is obviously bad because the fuse is there to prevent power surges, presumably the Dreamcast devs did that for a reason. Replacing with a resistor is really wrong, because you will cause a voltage drop in the circuit and probably end up with a bunch of weirdness if you plug in a full array of controllers and VMUs or something.

Nowadays we have a much better solution in PolySwitch fuses. These fuses are resettable - if they blow, simply turning the Dreamcast off and on again will reset the fuse and you can get back to playing. The F1 fuse that that needs replacing is rated at 390 mA (milliamps), Amazon sell near perfect replacement PolySwitch fuses at 400 mA.

DISCLAIMERS 

• I cannot be held responsible for any damage you do to yourself, your belongings, your friends, your family, or your household pets or anything else while following these instructions. This is all on you!
• I GIVE ABSOLUTELY NO WARRANTY on the correctness and usability of the information on this page. It works for me so I thought I'd post it
• No, I won't fix your Dreamcast for you
• The Amazon link below is an affiliate link, not sure why you need to know that, but full disclosure etc.

 

You Will Need

• 10 Pcs 72V 400mA Radial Lead Type PPTC Resettable Fuse PolySwitch 
• A Soldering Iron + Solder
• Some small long-nosed pliers 
• Desoldering Wire (optional)
• A cross-head screwdriver 

 

Before You Start

Turn off the power! Unplug the power cable! Switch the power switch on and off a few times to try to discharge the capacitors!

 

Method

1. Open the Dreamcast. You can do this by removing the modem from the side, and then removing the 4 case screws which are now visible
2. Locate the F1 fuse. It is the blue fuse on the right, next to the black capacitor and the ribbon cable. It is labelled F1.

3. Determine if you can desolder the fuse from above. Some models of the Dreamcast have this fuse soldered from the top. The model in the picture above has the fuse soldered from below. If your model allows desoldering the fuse from above then hold your soldering iron to the legs of the fuse and gently prise it away from the board with the pliers.
4. Remove the power board. Be very careful! The capacitors on this board may hold charge! Remove the two screws holding the power board and then gently pull it upwards holding the plastic clip on the side out of the way. Set the power board aside gently.
5. Remove the controller board. With the power board out of the way you can now remove the 4 gold screws holding the controller board. Leave everything else connected and flip the board over to find the solder points.

6. Locate the solder points. These are the two solder points directly below the second screw hole from the right in the image above. Double and triple check you've located the right ones!
7. Remove the fuse. Heat the solder points and gently prise out the fuse using the pliers from the other side. If you like, you can remove the solder entirely using the solder wire.
8. Add the resettable fuse. With the old F1 fuse removed, now put a new resettable fuse in it's place. Replace/reuse the solder points. Make sure you don't leave the legs of the new fuse sticking from the bottom or you'll short out the Dreamcast on the case! Make sure the solder points look as close to the original as possible (no wires sticking through or solder leaking over PCB tracks)
9. Put everything back together. Replace everything in reverse order. Make sure that the power board is seated firmly and that you screw everything down. Replace the case and the case screws.

That's it! Now you should power on and the controller board should work and you'll never have to worry about a blown fuse again!