exxos's Atari, Amiga & retro forum

frank.lukas wrote: ↑Wed Nov 07, 2018 5:00 pm

Pacman wrote: ↑Mon Oct 16, 2017 11:41 pm
Replacing the (noisy) cooling fan
The Noctua fan has a 3-pin female connector attached but there is no need to cut it off and replace it with the original 2-pin connector. Just make sure only the two leftmost pins (black and red wires) attaches to the Mega STe power supply. The yellow wire isn't used.

The Fan is connected between -12V and GND ...

+12V is wrong !

Are you sure?
Unfortunately I don't have access to my MegaSTe at the moment or I'd check with a multimeter. I did take a look at the power supply schematic though, and it might be +12V and -12V (instead of +12V and GND as I said), but you're saying it should be -12V and GND?
I'll check when I get things up and going again, but it may take a while, so please chime in anyone who can confirm/deny the above info.

Fan across -12 there. +12 is top of diagram.

Can also confirm -12 is -12 because of lower capacitor values on that compared to +12 which makes sense, also stated current 0.3A.

Thanks for confirming, Exxos.
Here's the corrected pinout. I'll also replace the pinout diagram in my original posting along with all the instructions to avoid any confusion (Oops: that didn't work -there's no "edit post" button there any longer. Any chance you could replace the diagram in the first posting with the one attached here?).

Just wondering if after all these posts on capacitors, Pacman should change name to Capman

Send me a PM with new images.. also link to the exact post where image is to be replaced and I will update it for you

RTN = GND

So the Fan is connected between RTN over a 10 Ohm (R35) Resistor and -12V. I replace R35 with a 1W/47 Ohm one ...

Exactly - it's not -12 and +12 as the new diagrams show.

It does mean that everyone might be running these fans "backwards". I need to look at how I connected mine.

Just a warning to anyone using the Noctua fan! I used the 'silent' slowest fan speed option at first, my PSU blew up and almost destroyed my TT. Since I got my PSU fixed I've stuck the Noctua on the highest setting, as the guy who fixed my PSU told me it overheated.

Steve wrote: ↑Thu Nov 08, 2018 11:45 am Just a warning to anyone using the Noctua fan! I used the 'silent' slowest fan speed option at first, my PSU blew up and almost destroyed my TT. Since I got my PSU fixed I've stuck the Noctua on the highest setting, as the guy who fixed my PSU told me it overheated.

Thanks. I'm indeed running mine on the slowest speed but I haven't used it extensively since the change.

troed wrote: ↑Thu Nov 08, 2018 11:40 amIt does mean that everyone might be running these fans "backwards". I need to look at how I connected mine.

I've been wondering about the same. So what is the original direction? Is the fan sucking new air in or blowing hot air out?