I was given a GW Instek GPD-3303s triple output power supply for repair. The unit did not have a voltage on Channel 2. Channel 2 was going into constant current mode whenever outputs were turned on. This implied that there was a short so I started taking the power supply apart. The cover was easy to take off. 4 screws on top and 6 screws in the back. I looked at the outputs of the power supply and I saw diodes across the outputs. I started looking at all three channels with a multimeter to see if the diodes aren’t shorted.

channeldiodes

Bingo channel 2 diode was shorted. I removed the diode from the power supply and turned on the unit. The power supply was able to output the correct voltage without any issues .It did not go to constant current mode.

removeddiode

The markings on the part are 1N5402. 1N5402 is a jellybean part and readily available on Digi-Key. I ordered the part and replaced it. Works like a bran new unit.