When I first got my Revenge From Mars from a local Pinhead; the fan was clogged with dust and grime. At the time; I simply cleaned the fan, removed the sticker, and added some oil to the bearings. This lasted about 3months before the fan began to make some horrible noises because the bearings were shot. I “lived with it”; but it remained on my todo list.
For years; I had watched threads about Pin2k in Pinside… always feeling a little guilty I had not eliminated the risk that my CPU fan would die… overheat the cpu… and put my RFM in jeopardy of force converting to NuCore or Pinbox. Today was the day I vowed to resolve that noisy fan.
First; I did not want to buy NOS (new old stock) of some 50mm fan made back in 2000 or some china knockoff that wouldn’t last another 18 years. I wanted a high quality fan with very little noise; but a good performer. I’ve grown to like the Noctura brand of fans because they aren’t cookie cut china knock offs. Noctura does not sell a drop-in-replacement for 50mm fans. Going smaller usually means less air flow with a higher “whine” because the fan blades have to go much faster to move more air. So I decided that I was going to try and use the NF-A6x25 FLX 60mm fan:
and build an adapter to fit the larger fan over the existing heatsink. This blog entry documents my solution, provides a TAPR/NCLed DXF for my adapter, and links to a Shapeways implementation of my adapter my fellow pinball enthusiasts to use.
First, I removed the CPU box from my RFM and pulled out the existing CPU heatsink:
Once I had the CPU heatsink free; I unscrewed the old FAN from the heatsink. This was done for two reasons;
- I need the heatsink to take caliper measurements in order design a 60mm to 50mm bracket.
- Eventually; I’d toss the worthless 50mm fan – but wanted to keep it incase I couldn’t find a working solution.
Obviously; the 60mm fan wouldn’t fit within the 50mm cavity of the heatsink; so I knew I wanted to use some 1/4inch clear Acrylic as an “adapter”. I went into qCAD resulting in a DXF file which I could then send to my laser cutter. I wanted to reuse the 50mm fan/heatsink screws and the 4 qty Vibration-Compensators provided in the Noctura kit. My second proto resulted in success and looked like this:
Reusing the 4 qty 50mm countersunk heatsink screws; I attached the clear acrylic bracket to the top of the heatsink. Then I put the 4 qty Vibration-Compensators provided in the Noctura kit thru the acrylic bracket and into the NF-A6x25 fan. The whole assembly fit together quiet nicely.
I carefully; reinstalled the fan-sink combo back onto the cpu and socket. This was a little tricky because the 60mm fan is bigger; but as you can see the whole contraption fits well:
Conveniently; my Pinball 2000 motherboard had a FAN header right next to the cpu socket; so I simply attached the CPU fan’s 3pin PWM connector to that unused mobo connection:
I powered up the Pin2k system on my bench with both the original and the new fan connected. !That old fan really needed to be replaced! This new fan is ultra quiet; I don’t think you can hear the fan over the PSU fan even when the box is open. You won’t be able to hear the fan at all when its in the backbox behind the backglass. Success!
I’ve decided release this design to the public under the TAPR Non-Commercial Open Hardware License which indicates:
You may make products based upon this design, provided you do not make more than ten units in any twelve month period for your personal use.
If you agree with the license terms; a DXF Drawing is posted here under TAPR/NCL license:
60mm to 50mm Fan Adapter Package
If you don’t have access to a laser cutter; you can 3D print this adapter from Shapeways: