Voltcraft Power Supply Maintenance

I got a couple older power supplies from the Voltcraft brand, so I decided to clean them up a little bit:

12V 2A - Replacing Selenium Rectifier

This unregulated unit had a selenium rectifier that started smelling a bit sweetly, which is the smell of impending failure. I replaced it with a silicon rectifier and also added a short circuit current limiting resistor, as I dunno whether the transformer is short circuit proof.

Originally it had a flashing red LED as a power indicator, I replaced this with a LED that is solidly lit when powered on, as I find the flashing annoying.

After load testing, I decided to replace the old 1000uF capacitor with a 4700uF one.

13.8V 3A(5A) - Cleaning

This regulated unit was seriously dusty. I took it apart and cleaned it, I also applied new thermal compound to the power resistor as it gets excruciatingly hot. After reassembly, it stopped working - which I figured out to be due to a cold solder joint on the bridge rectifier.

I also replaced the main cables from the switch to the transformer, as they were fairly sticky.

Rubber Feet

One of the rubber feet inserts was missing on the 13.8V one, so I 3D printed a replacement using TPU.


OpenSCAD source:

union() {
  cylinder(h=1.5,r=3.5, center=true);