Hello I had a derailment I didnt notice that was being powered by Fixed 1. This is an original TIU (No revision number on it). After the derailment I do not get red LED light. I was able to get around this by using an auxilliary power supply and switching to Fixed 2. The variable channels work correctly. I am doing a major layout revision and thought I would check this more closely. This early unit has no fuses I can see. When I meter fixed 2 I get read 0 ohm continuity on both red and black in to out. fixed 1 shows red continuity but black is open. I thought I read in a long ago post that this revision TIU cant be repaired. Any suggestions on this would be helpful.