TIU REV.L

Possible a shorted FET, but that means both channels failed together which is unlikely unless you some how wired them out of phase or caused a dual short or voltage spike on both channels.

I would do a TIU reset and also test with TIU off the track and just powering a simple lighted lock on or lighted accessory.  This can ensure TIU is at fault and not some crossed wiring feeding power back into the TIU channel from a different source.  G

Hi GGG I did a reset and tested it off the track. Still have the same problem.

Strange one...You're saying the fxd key does nothing?

Menu/  system/ dcs set up..... FXD is like a toggle switch that toggles the var channels  between FXD and Var mode... The remote tells you what mode you've selected.

 Trouble shooting.... If var 1 &2 IN are disconnected  do both  channels still stay on??

Gregg The fxd key does nothing.  trouble shooting if var 1 and 2 in are disconnected do both channels still stay on. No

Assuming you did a factory reset of tiu#2  it's address would now be tiu #1... Both tiu now have the same address.

the originasl tiu #1 would have to be powered down if one wanted to try testing the other... Does the read find tiu? how is it powered ? etc.

Is there a dcs signal on the var channels etc.

And the big question , what happened  for no apparent reason....?  

Gregg What happen for no apparent reason. I had a transformer out of phase. I unplug my trans every summer because of out power surge and outages. I have 3 out let boxes , one is out of phase. One trans was plugged into this. Any how all fixed now. But I need to fix my TIU do you know anyone. Thanks for help. Mark

You might want to look for a connection between the variable channel and a fixed channel, such as adjacent center rails that are touching.

Barry I will do that. Thanks