Power Supply Safety Covers for Astron RS-35A

thingiverse

This is a set of safety covers for an Astron RS-35A power supply. I use one of these supplies to power my ham radio equipment. It is reliable, quiet, and produces clean electrical output. There is, however, one thing about this power supply design that bothers me -- the four exposed transistors on the back. (See photo without covers.) They are isolated from the case and heat-sink, and carry a voltage of about 24V. The main output terminal is also exposed, although it should be obvious to shield that. A stray conductor can easily contact these points and short them to ground, or carry that voltage (at high current) back to other equipment. This *will* explode your gear. It happened to me when a USB cable connector made momentary contact with one of the transistors. The connector was burned off within a couple of seconds and a nice piece of equipment received about $150 worth of damage. Don't let that (or worse) happen to you. These guards are cheap insurance. The guards attach to the supply with 8x3mm round magnets that I sourced at a local hardware store. They are a press-fit into the holes, and I also used a drop of super glue to secure them. Design files for Autodesk Fusion 360 are included so that you can adapt this design to other magnets or another power supply. (Please give attribution for any remixes.)