[LDS]

I can't speak for the D-Control specifically, but if you ground a regulator's heat fin it will often cause it to stop working. It usually needs to be electrically isolated from ground. It is an easy thing to do with small PCB mounted ones that have a heatsink that just floats in air, but for bigger chassis mounted heatsinks, you usually need an insulated heat pad between the regulator and heatsink, as well as some consideration about how the nuts and bolts keep them both together. Often there is a small plastic washer on the regulator side to prevent metal on metal contact. I always seem to mess it up though, as the bolt shaft can still make contact. I usually use plastic nuts and bolts which work quite well.

It might be a case that you need an insulated heat pad between the heatsink of the PSU and the chassis. They also often get called thermal gaskets, and are a sticker on one side. Peel it off, stick it on, and press it all together.