Ensiniq EPS cooling fan

I’m thinking of installing a cooling fan somewhere on or in an Ensoniq EPS.
I’m looking at the schematic - can I run it off the 12v going to the disk drive motor?
Seems least intrusive as far as if there’s any (audio signal) noise concerns.
The fan I’m looking at is a 12v brushless DC 50 milliamps or so.
My question is: can the regulator handle a little bit more load?

Good idea, those Ensoniqs can run pretty hot. The 12 V disk motor power is regulated by a LM7812. LM7812 can provide up to 1 A of current. Floppy drive motors can use quite a bit of current but I doubt the 50mA added would push the 7812 past its limit. However, I’m not sure an internal fan would much improve cooling due to there not being any vent holes in the chassis, for a fan to be most effective you need a fresh supply of cool air and an exhaust for the hot air. An external fan aiding the heatsink on the back could maybe improve thermals more effectively. And if you go with an external fan it may be more worth it to build a small 12 V power supply or simply use a 12 V wall wart to power the fan.

Thanks Travis,
I appreciate the specs info.
I went ahead and installed the fan the other day after some more research.
I mounted a small 25mm fan to the outside of the heatsink with a tiny bit of gorilla glue.

There happens to be two small holes in the heat sink unused, so I ran the wires through one of them and then down under the PS board where I soldered them around the + and ground of C17.

It works well. I let it run for several hours yesterday.
Never gets hot, just warm. Fairly big difference.

I’ll make sure it’s stable for a few days and then post an update with some pictures in case others want to try it.

Thanks again for your help.


I did a similar thing with my EPS-16. It helped alot. I also attached low profile heatsink of all main chips and(used double sided thremo-conductive adhesive tape.

The fan i used was from an old laptop and was able to orient the air discharge to the most needing ICs. The fan was fixed to the to right corner.

I suggest running an extended test to make sure the fan doesn’t cause the PS to overheat possible introduce noise. Brushless motors have circuitry that generated hi frequency signal to drive the motor.


Good info thanks.

I let it run about 8 hours at a time for a few days. Doesn’t get hot. No audio noise.
I picked that point in the circuit for fan power because it’s after the 12v regulator but before the 5v filter caps for the analog board, thinking this would be the best chance of any noise being filtered out, and it worked as expected.
The actual fan itself makes a tiny bit of physical noise (not in the audio) but it’s not an issue. I’m sure there are quieter fans out there.

Another update / upgrade:
I installed a Gotek Floppy Emulator which doesn’t use the 12v rail at all (just the 5v). So now the only thing running off the 7812 regulator is the 70Ma fan.
Runs even cooler now. I should mention that I re-capped the entire thing before doing any of this (all electrolytic capacitors on all boards) so it has the best chance to run stable.

Thank again everyone.