Bypass fan?

[gdskater]

I would like to know if you can use the DC without a fan and not let it overheat or shutdown.

[Matt]

The controller board senses the fans RPM speed, if is below a certain level the DC will not run.

You need to make a 555 Circuit to give the pulses to make it think there is a fan there, you can buy the chips and components separately or, the easyier option which is buying a little 555 timer kit.

It will overheat if there is no fan at all

[Pyrosurfer]

I'm pretty sure the RPM thing is crap. I measured resistance from gnd to the extra pin to gnd and it was a constant .88k. The rpm method is probably just acting as a load for the dc's current. People here have said before they just shorted the extra pin to gnd, and it worked. Both of the RPM method and shorting could be harmful to your dc, I would recommend putting a 200-2k resistor from the extra pin to gnd. I will be trying this myself soon.

[Sir Savant]

Dont forget the fan!

[Alexvrb]

I would like to know if you can use the DC without a fan and not let it overheat or shutdown.

Not recommended, unless you plan on running it in a larger case with lots of ventilation, and bigger passive sinks. Heck, even then I don't really recommend it. However, you could use the method(s) mentioned above to help you replace the fan with something very similar. If you wanted to, you could even use a larger, slower fan, if you wanted to do a lot of work.

[DuffMan]

Why would you want to take the fan out in the first place? Its not noisy and isn't in the way of anything.

[dcmodder]

yea but when one of the blades on it breaks off it is kinda noisy. that was my problem.

[kram2048]

I would replace the fan with a better cooling system (thus multiple fans, just like in my PC)

1.) a fan for the PSU, exitting the case

2.) a fan and heatsink for the CPU

3.) a fan for the VPU

4.) a fan for the SPU

5.) even a fan for the clock chip and an external intake fan and 2 side mounted output fans near the opposite side of the machine

also I would add a PC PSU power cable, since 12V = red, 0V = black, 5V = yellow, 3.3V = orange, and -12V = white

[Caboose]

*sigh* Thank you DCmodder

[Matt]

Your not going to be able to fit all that in unless you find some really nice low profile sinks. Good luck

[Alexvrb]

I would replace the fan with a better cooling system (thus multiple fans, just like in my PC)

1.) a fan for the PSU, exitting the case

2.) a fan and heatsink for the CPU

3.) a fan for the VPU

4.) a fan for the SPU

5.) even a fan for the clock chip and an external intake fan and 2 side mounted output fans near the opposite side of the machine

also I would add a PC PSU power cable, since 12V = red, 0V = black, 5V = yellow, 3.3V = orange, and -12V = white

Even with size and power (fan draw) considerations aside:
1) Not really necessary, and if you make that an exhaust fan instead of an intake, then you fight the airflow set up by the original fan.
2) It already has a heatsink/heatspreader, and the case fan acts as a fan for it and everything else. It was actually pretty well engineered to only need such a small fan.
3) Not unless you're overclocking it.
4) Never necessary, nor desired, ever. It barely gets warm to the touch.
5) "Clock chip"? See 4. All the other stuff? Massive overkill. Massive.

Look, I'm all for extra cooling. But the Dreamcast is not a PC. It doesn't run that hot, and its in a very small case. After a certain point, in PCs or DCs, extra fans stop helping. You might as well replace the PSU and watercool it. If you want a more reasonable significant increase in cooling, replace the stock fan with a larger, but quieter fan. Something that can push more air, and bring down the case temp. If you really wanted to, you could add an intake on the opposite side to supplement it. But with Dreamcast, all you need to do get the case temp down and the metal will do the rest - the DC just does not put out a ton of heat.