exxos's Atari, Amiga & retro forum

Hi guys,

I'm aware that this is perhaps not the most pressing / interesting issue you can have with your Falcon but I'm interested in your opinion anyway.

For some time I have been installing Noctua fans in my Falcons. Today I was messing with one of them and it reminded me of one interesting issue: that Noctua fan actually doesn't really fit 100%. It does seem to fit but in fact it stands out of the bottom PCB a little:


And so what, you ask. But if you take a closer look to a perfectly fitted motherboard:


you see that there's actually very little room for any stand outs at all. So what happens is that this creates some pressure towards the metallic bottom part which in turn create pressure towards the PCB. Not only in the fan area but also near the DSP SRAM for instance.

Without the fan:

With the fan:

So I'm quite concerned that the points where the fan touches the metallic bottom (especially the ones more distant from the viewer, towards the PCB) then create quite some pressure because of course with all the screws in place those "floating" parts of the bottom shielding will be aligned with the PCB.

So I've been thinking:

• is this really an issue? (IMHO it is)
• should I drop the fan entirely (the easiest way out but I don't like it -- it doesn't look good, I use the shielding so it helps the airflow a bit, ...)
• should I remove those rubber pads from the fan (this would make it "compatible" with the original fan but certainly lose most of its silencing features.. however now I see that even without them the height is close to 11mm actually)
• should I remove the part of shielding beneath the fan (ewww.... not looking good + the gain is about 0.5 mil at most?)
• should I lift the fan's bracket by one mil? (this looks like the best compromise however one has to be careful not to lift it too much otherwise the keyboard wont fit)

Any opinions, ideas? :)

Bending the motherboard is a concern as you rightly pointed out. If people are doing that, then they should have their falcons confiscated !

Have you looked into fluid dynamic bearing fans ? I had them in my store I think. They fit well , offer good air flow and are quiet.Though all fans are not created equally and simply trying a few to find which physically fit is the way to go.

Any bend on a mainboard, especially that age, should really be avoided, so I agree it's an issue. Flex killed one of my Megas (Now repaired) so should be avoided at all costs. Admittedly mine was a sudden flex when I plugged something into the Megabus slot, but it amounts to the same thing: mechanical stress.

As for solutions, there may be some low profile options that will work, though how silent will they be? Is the fan noise worth avoiding bending the mainboard?

Unfortunately some fans are made with the approach that the size rating is just a guide and if someone can line up the mounting holes all is well. The worst I ever had was a "Gelid" fan, sold as 15mm thick but actually very close to 16mm. Critical in the Mac it was supposed to go in.

How about cutting out the plastic casing under the fan and maybe cover the hole from the outside with thin mesh like they use on front panels of "gamer" PC cases?

Wouldn't that hit 3 birds with one stone?

1. Make room for Noctua
2. Remove airflow restrictions of the casing which only has small holes for air intake
3. Let less dust into the Falcon that the original setup

What do you think?

PS: how many of you dare to run the Falcon with no fan at all? (and case fully closed, with shielding and all ;)

Considering that the case alone can go on eBay as high as 500+ EUR I wouldn't be so keen on doing this.

Have you thought about modifying the noctua? I seem to recall when I put one in mine that I did some sanding on the fan (housing).

I removed the rubbers in the corners at the top and bottom. The fan is still super quiet and fits without any problems. At least for me... ;)

I use a Sunon - Maglev fan in mine. It's exactly the same size as the original Falcon fan, but super quiet. I put some resistors in-line to lower the speed as well. Sorry I don't remember the model number though.

The Sunon are good too! Could this be it?
This one is installed in another Falcon of mine.

Sunon
40x40x10mm
HA40101V4-999 DC 12V 9.00 m³/h