I take it the greater concern is heat dissipation, would Vaseline be a bad choice or good choice?
Richard Chapple Sr said:
I take it the greater concern is heat dissipation, would Vaseline be a bad choice or good choice?
Bad choice.
You need a heat conducting grease.
Try your local Radio shack.
Because you can tighten down the stud types nice and tight, don’t worry so much about the thermal grease. The original setup had the plastic holder pressing the diodes to the metal, much less positive (and cheaper)… thermal conductivity more important there…
Greg
Thank you everyone for your input. The link to the proper diodes that Greg supplied did the trick. It was an easy fix. drill two holes in the heat sink for the studs and make sure they don’t touch the metal cabinet when finished.
Yahoo, the railroad is up and running again.
Dick
Richard, doesn’t that make you feel good? Fixing it yourself! 
It sure does David:
I had to call my model railroader friend two blocks down just to tell him I had actually fixed something that works, and it took all of 30 minutes.
Usually when I say to self…that’s easy…it’ll only an hour maybe…it will be 3 weeks later with more cans of worms opened up. LOL
What a relief to see trains running again.