MiSTer FPGA Forum

I'm getting a Noctua NF-A4x20 to replace the stock fan on my I/O board (v6.1, MiSTer Addons). Does anyone know specifications for screws and nuts that would fit as well as the stock fan? I can figure it out myself of course, just was hoping to save a little trouble if others have already done the research. Would it be 20mm long screws?

I'm using a Checkmate A1500 Mini case and plan on taking 12V off its power supply instead of 5V from the I/O board so I'd get the NF-A4x20 FLX.

They are M3 sized for bolts and nuts, maybe go with 25mm length, as the fan you are going to use is 20mm thick, you need to pass through a 1.6mm thick PCB.

Xbytez wrote: ↑Mon Jul 18, 2022 6:38 pm They are M3 sized for bolts and nuts, maybe go with 25mm length, as the fan you are going to use is 20mm thick, you need to pass through a 1.6mm thick PCB.

Thanks. Such screws are measured from the bottom of the head, correct? It looks like the fans are indented to fit the head, so I'm thinking maybe a 22mm would be even better? 22mm M3 socket head screws. I'll probably get an assortment with both 22 and 25mm.

edit: Then again there are rubber pieces that stick out a bit so the fan may be effectively thicker than 20mm.

thisisamigaspeaking wrote: ↑Mon Jul 18, 2022 8:07 pm Such screws are measured from the bottom of the head, correct?

Yes.

Use M3 cap head bolts these will fit neatly into the mounting holes on the fan.

Xbytez wrote: ↑Mon Jul 18, 2022 10:00 pm

thisisamigaspeaking wrote: ↑Mon Jul 18, 2022 8:07 pm Such screws are measured from the bottom of the head, correct?

Yes.

Use M3 cap head bolts these will fit neatly into the mounting holes on the fan.

Thanks, M3 are perfect. 22mm turned out to be a good length, there's not much sticking out past the nut (less than on the stock fan that came with my board). 25mm would work too but I felt anxious (probably needlessly) about anything sticking down. The rubber feet (grommets?) on the fan make for it to hold pretty tightly but I am wondering if I should put some Loctite 222MS on the screws just to make sure a nut doesn't fall off onto the DE10-Nano board at some point down the road.

The noctua fan comes with those long rubber things for mounting vibration proof. You can use those instead of screws.

C-R-T wrote: ↑Sun Jul 24, 2022 1:51 pm The noctua fan comes with those long rubber things for mounting vibration proof. You can use those instead of screws.

I think those would leave a lot sticking out on such a small fan.

You’re supposed to cut off the excess.

C-R-T wrote: ↑Sun Jul 24, 2022 2:50 pm You’re supposed to cut off the excess.

Several issues. If my understanding of how to deploy them is incorrect I'd love to know the right way to do it.

• The part that would go through the circuit board and hold it in place (the "tip") is quite a bit larger than the tip of the screw and nut currently in place, and trimming this might be difficult since it's silicone (or whatever kind of rubber), might compromise the tip's integrity, or might result in the board being scratched or damaged.
• From my understanding it can take considerable force to pull the tip through the holes which seems risky for the board and its components.
• The cap/buffer piece at the other end is meant for larger fans and does not look like it would recess in the area available on such a small fan, potentially meaning the fan would not sit flat against the PCB.

you can use the rubbers it comes with just pull them through and trim them off worked for me

fraggore@sky.com wrote: ↑Tue Nov 01, 2022 6:59 pm you can use the rubbers it comes with just pull them through and trim them off worked for me

Is the fan sitting flush against the PCB? It'd be great to see a picture of how it turned out.