Ender 3 NG v1.2 spring test probe adapter for connector-less panel fans

I always thought attaching and removing a JST XH connector when handling the electronics panel cover on my Ender 3 NG v1.2 was cumbersome, and I knew in the back of my mind that the cable will probably eventually break after handling it enough.  So I created this bracket to deliver 24V to two spring test probes, which makes contact to a couple strips of copper tape on the panel to deliver power to the fans!

The best way to print this model is with the test probe holes face down.  Grid supports should be added to the bottom of the print.  This does mean that this surface might be a little stringy, but it'll be hidden behind an electronics vent, so no biggie.

To build this model, first solder a couple wires to a JST XH connector.  Then, push it into the model (as pictured).  Since part of the connector hole will be printed as a bridge, it may have bowed on one face, and you may need to scrape the plastic off a little bit to get the connector to fit.  When the XH connector is in, drop a drop of super glue over the back to secure the connector in place.  Let cure, and you can add some heatshrink to the pins if you'd like.

Then, press the spring test probes into place (as pictured).  They should have a snug fit.  You may need to clean up the lowest layers of the hole, since they are also printed as bridges.  Put a small dab of flux on the ends of the probe pins, and tin the surfaces.  Cut the wire on your XH connector, tin the ends, then quickly solder to the probes.  And add some heat shrink over the probes!  There will be 24V directly connected to these probes, so having large exposed metal is asking to pop a FET on your MCU with an accidental short.

After the connector is built, remove your electronics panel cover and remove the fans and fan shroud.  Cut two strips of 6 mm copper tape a little longer than the shortest distance between the fan hole and the panel edge.  Cover the ends with some masking tape as a solder mask, add a touch of flux, and tin the ends.  Clean your panel with isopropyl alcohol, and lay them between the fan hole and edge of the panel (as pictured).  Then, cut your fan cable, tin the ends, and quickly solder to the tinned copper tape.  I had some transparent sticker paper handy, so I cut this to size as insulation.  You can add tape, if you'd like.  Place the fans back in the shroud and assemble.

After the bracket and fans are ready, you can now install the bracket to the inside of the electronics panel using an M3 screw and T nut.  Place the edge of the panel inside the panel recess, get the alignment of the bracket correct, then tighten the M3 screw.  Run 24V to the JST XH connector, ensuring that you are using the correct polarity for your fans.

Now pop that panel on, and viola!  Fans work without a connector!

Here's the BOM for this model!  I'm including the laser sticker paper because it's what I used, but you can certainly cut some tape to fit, too.

• BORDSTRACT P156-D spring test probes: https://www.amazon.com/dp/B0CC2GF6YX
• 2-pin JST CH connectors: https://www.amazon.com/dp/B0B2R966ZY
• 6 mm wide copper tape: https://www.amazon.com/dp/B09WGYP2VR
• Laser sticker paper: https://www.amazon.com/dp/B087CNQ75R

This model is like this pogo pin bracket, but instead of pogo pins, it uses large, gentle, 4 mm dome-shaped spring test probes.  I highly recommend this model over the pogo pin bracket, because the pogo pins are sharp, and will likely tear holes in the copper tape over time.

Here's a model for a fan shroud with fan grills and no connector hole that is designed to work with this mod.