TIU not working properly

I have to guess that you've since disconnect the layout and are reporting no output right at the var #2 output? So there's no short at the track? and the power is OK going in?

Not much else you can do I believe. The TIU has TVS devices to protect incase of shorts and they fail shorted usually I believe. If failed open, you wouldn't know they've failed. So yours is not passing voltage and then, you must have cooked something else internally. Being an older model they might not even have the TVS protections? You should look on the bottom cover and report to the techs here what version TIU it is.

 You did try swapping the input power and made sure you're methodical in your testing? (Always no output on Var #2). I assume your testing with some type of meter for power in and out? Var #2 doesn't show a short?

 Sorry for the stupid questions but there's no telling what level a poster is at.

Joe,

I took all my loco's off my tracks. I pulled all the cars out from the tunnel they were in and there was one truck on one car that was still derailed & was probably shorting out the TIU. I corrected the issue but I still get no output on variable#2. I'm using a multimeter to check for voltage. I swapped input wires and there was still no voltage on variable #2. My poster level for electrical issues is pretty low.

Thanks,

Don

There is nothing on the TIU to tell me what version it is.

Your level is probably above mine!

I think that means your TIU is the first edition then? I thought those did not have internal fuses though?

Might need to wait for a tech to post here for more help. I believe she has to go in for service.

Thanks Joe,

I think I'll just buy a new one.

Don

Check the fuse or circuit breaker for the transformer for variable channel #2.

Barry,

I show 18 volts on all inputs on the TIU. I have 18 volts on all the outputs except variable channel#2. I just checked the Z-4000's circuit breakers just to be sure and they were ok.

Don

It can be repaired.  G

I realize your self-proclaimed electrical level is what it is, and if you've been meaning to buy a current version TIU anyway then so be it.  But for DIY enthusiasts handy with a soldering iron, the TIU FETs (4 per variable channel) can be had for 10 cents each on eBay (free shipping from Asia).  

Thanks Stan, that's a lot cheaper than the last ones I bought, I just ordered 30 of them.   Beats the Digikey price by about 15x, and I thought they were cheap!

Thanks everyone,

I sent my TIU to Ray Manley, who has worked on a few of my loco's and updated my TIU. I have essential tremors which doesn't make it a good idea for me to try soldering small items. I hope lots of people can use Stan's information. 

Thanks again,

Don