Korad KA3005P Repair

The Velleman PS3005D (or more commonly known as the Korad KA3005P) is a good linear power supply for those on a budget. I acquired this one in a broken state, although thankfully it turned out to be an easy fix: the display board needed re-seating, and the fan needed replacing.

Fan replacement

When powered up, the unit would make a horrible grinding sound. It would last a few minutes and the settle down. Guessing that the fan bearings were worn out, I replaced the fan with a new silent variant. The fan is a 80mm 'dumb' (i.e. not PWM/4pin) 12V fan; its speed is controlled by the main logic board PWMing its power supply.

Display not turning on

The unit would power on, but neither the seven segment displays nor the LEDs would illuminate. I took apart the unit, seperating the display board from the main logic board. Seeing nothing immediately wrong, I reassembled it, which actually fixed the issue. I suppose that a loose connection had developed in the board-interconnect at J4, and reseating it solved it. I was pleasantly surprised to see that someone has designed a replacement LED board, if I had needed a replacement: https://github.com/djedditt/ka3005p-display