PCB Jig + Lab Power Supply #DIY

I recently added a couple home-build devices to my home lab. The first is a well-designed PCB jig engineered by an electronics forensic expert. The second is a very cheap lab power supply using a Chinese step-down converter and an old battery charger.

The Jig

It seems I never have enough hands, especially while testing and troubleshooting a fresh PCB. As frustration was mounting recently, Thingiverse member Giufini seemingly heard my prayers – and shared his design for a PCB probe jig!

Thingiverse photo

At first glance, it looks somewhat hap-hazard. I built one, and must say that it is very well designed! The layout of the board is perfect for the PCB’s I work with. The towers and arms are easy to adjust and have a well-tuned flexibility to them. Finally, the acupuncture needles were simply genius! This design was even reviewed (and quite well received) on Superhouse.

PCB Probing Jig DIY

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Cheap Spindles & Power Fluctuations

While building my CNC mini-mill, I purchased a 500W air-cooled spindle from eBay.  It came with a power supply, which looked great and I (falsely) assumed it would work perfectly on my home-built mill.

Boy was I wrong!  The mill worked great as long as the spindle was turned off.  Whenever the spindle was on, there was a chance that the mill’s microcontroller would reset (bad), lock up (worse), or would suddenly enter an infinite loop (really really bad!) and an axis motor would begin moving in some direction until I noticed and stopped it.

After much work identifying and rectifying the causes, the power supply has finally been tamed.  Here’s a guide for anyone having the same issues.

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