Even though it was an improptu kitbash, I am sort of proud of the job. On the other unit, I just kitbashed a microUSB plug and about 3” of wire to reach around and plug into the microUSB socket on the side of the RPi3B board. It looks really ugly.
Here is a photo of the one on the RPi4 DRAWS unit :
After clipping off the “push on” connectors (I hate those POC!), I trimmed and threaded very thin heat shrink over the wire pair and pushed it all the away up until it stopped against the fan body, leaving the ends of the wires out about ½”, then used the hot air tip on my rework unit to shrink on the piece. I then stripped off about 1/8 inch of the insulation from each wire and tinned them carefully with “no lead” solder. I threaded the assembly through the slot like you see above, then using a fine tip on the soldering tool @ about 750F, I carefully tacked each wire to the appropriate solder pads of one of the USB connectors (that would be pins 1 and 4) on the bottom of the RPi4 board. After assembling the case around the two boards, I used a couple of 10mm long (M2) machine screws to fasten the fan in the case holes (too long but what I had – they are clear of anything inside the case). I used 6 of the remaining M2 flat head screws that came with the case kit to finish attaching the case cover.
I am pretty casual about kitbashing stuff… this RPi4 was the first one I bought (1GB ram)… it was “expendable” if I screwed up. Fortunately I did not and the unit works like a champ. I had hoped to drop the temp farther, but this was enough to bring it out of the alarm zone.
I hope my description makes sense.
Jack Spitznagel – KD4IZ
Science River LLC
Biomedical Consulting Services
I'm curious how you routed your fan wiring? I don't see them in your picture? Would you be
willing to share your install?