Question on TIU Outputs

Are there locos on a powered section of track fed from variable 1?  When power is turned on, do you hear a clcok from the loco?  Do you have a feed from transformer to variable 1 input?

Is there a power source for input 2?  Each channel has to have it's own power source.

John,

I have my transformer (MTH Z750) going to VARIABLE VOLTAGE IN1, and jumpered to FIXED VOLTAGE IN1.  The wires going to the track come from VARIABLE VOLTAGE OUT1.

With the pushing of the proper handheld buttons, this will allow you to run DCS engines as well as Conventional engines.

I have the following.

Transformer input to Fixed 1 and Fixed 2 in parallel.  The only thing connected to the outputs is the track feed from Output 2.  Output 1 is not connected.

If I move the track connection to Output 1, it finds the locomotive.  If I just move the connection to Output 2 and power back up, it tells me there is no DCS Locomotives on the tracks.

I seem to be back-sliding here, I'm sure I had it work on Output 2 once connected the same way.

Garbage in = garbage out.  Nothing in = nothing out.  You can't get output from a TIU circuits unless you have input to that circuit.  Unless you have a Rev G TIU, the 4 circuits are insulated from each other.  A Rev G has the 4 blacks outputs connected to each other.

RJR, did you read what I posted?  I have a transformer connected to both inputs, and I get the 18 volt track power from output 2, just no DCS operation.

This is a Rev. L TIU.

I get voltage out on channel 2, just no DCS operation, that seems to indicate this is not a fuse.  Curiously, the locomotive doesn't wake up in conventional mode, just sits like it does when there is a DCS signal.  However, when I do a read I get no locomotives on the track.  It appears it's seeing a DCS signal or the sound would come on like it does with the transformer connection.

I saw the variable DCS settings, but I'm not worried about those outputs just yet, I want to get simple working.

Edit: OK, I figured out the reason it doesn't do conventional, the TIU was sitting next to the track, probably coupling enough signal to keep it off.

John, did you by chance buy this TIU from a hobby shop located on the site of an old Indian burial ground?

John,

If you momentarily disconnect the #2 output from the track does the engine start up in conventional when re-connected?

And if your wiring permits, if you reverse the #2 power cables (red to outer rail, black to center rail) does it behave the same?

How did you know that?  

gunrunner:  you specifically said "Transformer input to Fixed 1 and Fixed 2 in parallel"  NO mention of anything connected to a VARIABLE INPUT

Yep, it started in conventional when I reconnected.

As to the second point, won't that risk blowing a fuse if the inputs are out of phase?  Are there no common connections between the channels?

I'm not doing anything with the parallel outputs or inputs.  I'm supplying power to the two fixed inputs, and power comes out the two fixed outputs, but DCS only works on fixed output 1.

Have you checked that the DCS is turned on for that channel.  Menu System DCS Setup

check the setting for fixed 2

I made sure that was on, turned off the TIU, waited 10 seconds, turned it on.  Still no DCS locomotives on the track.

Good point though, I found the variable ones, didn't know you could kill it for the fixed ones as well.

Edit, I mean variable, I need to learn to type!

My thought was to isolate #2 which is apparently the problem.  So assuming it's a DCS communication problem, can you hook #2 output to, say, a few feet of spare track with the correct and backward polarity. The engine won't mind and no fuses should complain.

The only time I've seen something like that, we had swapped the outputs.  Red to black, black to red.  But, I'm guessing you've checked for that.  You should probably verify phasing, but I'm not sure that would matter in this case unless the engine bridges a block.  Then, for a brief period of time, it will matter a great deal. :-)

It's not clear to me if you have two transformers or not.  If you only have one, make sure you haven't crossed the inputs. I'm not sure what that would do, but it might cause a problem.

Mike

I would wonder if the signal generator on fixed 2 has died. If it has, you would get full voltage out of fixed 2 output, but no DCS signal. Try powering the TIU with auxiliary power, eliminate your connection to fixed 1in and fixed 1 out. You should then have your Z750 powering Fixed in 2 and fixed out 2 powering the track. If DCS still doesn't work, then I would suspect the signal generator, which is an MTH repair. I have had this happen on fixed 1 twice.

Actually, it was the track wires switched under the track! I was rewiring trying to sort out my original issue and swapped the wires.  I'm surprised it worked on channel 1 that way but not channel 2.

I have this all sorted out, I'm back to my original issue.  I'm currently doing a test to see if it's still crapping out after 1/2 an hour or so, we'll see...