TIU Melting Issues

Adriatic posted:

Overtightening the thumbscrews beyond the needed torque to get the inner nut loose on thumbscrews next removal is the root cause.

When you're pulling higher amps thru the lugs, they should be tight. The way the posts are tapered, prevents overtightening. Unless you are locking vise grips on them? We are talking about hand tight, right?

 If they are properly tightened inside with locktite on the threads, there should not be an issue. The brand new "L" version I opened up, had the lug screws loose. They were not even snug. So I believe that root cause was from the factory not tightening them properly. 

To fix the dual female binding posts on the TIU:

1.  Remove the nut, locking washer and wire with its terminal
2.  Replace nut on binding posts and tighten
3.  Place the wire with its terminal on next
4.  locking washer next
5.  New  M4 .70 nut next and tighten

This is the way the Z4000 transformers that I have had open and I haven't seen the problem with binding posts coming loose on those. I have no idea why the TIU are done differently. With the wire terminal between the two nuts locking washer is much more secure in my opinion.