Hi Tim,
(Updated after my initial post)
Check this diagram of the PS board with the details of the transformer, Q1, etc.
If you look at the diagram (below), you will see item 34, which is the screw that attaches the PS board to the T1 transformer, which is then itself attached to the side of the chassis unit. This was the case in the last unit we worked on, IIRC. This is as it comes from the factory.
The molex connectors on these units were problematicand caused power supply problems. There were issues with the metal used in the contacts and they would go bad in short order. See the notes on the Quantec web link. There is a good diagram relating to this.
The regulator attaches to a small heatsink. And as I recall was in turn bolted to the front panel to further aid in disapating heat from Q1. You can somewhat see this in the diagram above, item location #29 and in the diagram at the top of this post.
So I gather you are missing the heatsink, obviously...after re-reading your post. I don't recall the exact size or shape of the heatsink. It's been a long time since working on that particular unit. But should not be too difficult to fab either a piece of aluminum stock or channel, adapted to attach to both the regulator and the front panel.
Here is a link to the QRS PS Schematic (it's too big to post here):
http://www.quantec.de/docs_e/fix_qrsps_sch.html If you can post a pic of the inside area of the PS, that may help jolt my brain cells to recollection.
Regards,
TWJ
GRS Systems