# Z-4000 Track Power to TIU and Signal Strength from TIU -- Isolated problems



## Locomods (Jun 16, 2020)

Large MTH DCS layout idle for 12 years of wife's terminal health problems has a few dead signal spots (power is good). Some improve with cleaning and I plan to try some light bulbs or filters soon. I use 3 Z-4000 with 3 TIUs and need to check my logic. All TIU outputs used as fixed and set at 18 volts from the Z-4000. So a TIU gets two sets of wires from a Z-4000. One from each handle goes to one side of each TIU so those 2 TIU inputs are jumpered together on one power source so that each TIU effectively has 2 power inputs -- one from each Z-4000 "handle." I see this as about 175 watts input to each half of each TIU (The Z-4000s are only good for about 350 watts out which is about 175 watts per side. Each TIU output (4 from each TIU) goes to a terminal board that is located near the middle of each block zone. The 6 blocked zones are separated electrically by insulated center rails. This works pretty well with 7 to 10 signal strength except for 3 or 4 trouble spots where signal strength suffers (so commands and feedback suffer) but trains run on through, doing whatever they were told to do last. I am leaning towards experimenting with 18 volt light bulbs or building filters if I can figure out proper Resistance and Capacitance and whether they are in series or parallel. 

So: Is my thinking on power distribution ok? Light bulbs on the terminal boards at troubled outputs and or at TIU outputs? If filters, series or parallel and values? 

By the way there are about 600 to 800 feet if track and 50 or more switch turnouts (all on dc control -- work great). And I also have a TMCC command base attached at one spot near the center and the TMCC locos work very well on CAB 1 or DCS Remote. So I think the control issues have to be with the feedback handshake of the info control packets between the TIU and the PS2.0 locos in those few track areas. And the TIUs get their operating power through the aux jack from individual 2 Amp, 18 volt wall supplies that I have scrounged over the years. 

It's a load, but now that my wife has passed, I need to get back into this outlet for my sanity.


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## DonR (Oct 18, 2012)

Locomods

Your post is correctly positioned here in this technical forum. However,
I notice that none of the many 0 scale members have responded.
They include many using the MTH systems. It may be helpful
to post in the 0 scale Forum a reference to this post. MTH systems
are quite different from the DCC systems so many of us use.

Don


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## Locomods (Jun 16, 2020)

DonR said:


> Locomods
> 
> Your post is correctly positioned here in this technical forum. However,
> I notice that none of the many 0 scale members have responded.
> ...


Thanks Don. I will see if I can figure out how to do that. (I think just copy/paste)


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## gunrunnerjohn (Nov 10, 2010)

Please don't start duplicate threads on the same topic. If you want something moved, a mod or admin can move it for you.

FWIW, the reason I didn't respond is there is no useful response I could make. 


Locomods said:


> By the way there are about 600 to 800 feet if track and 50 or more switch turnouts


With a layout that size, there are countless things that might be wrong. In order to actually provide intelligent answers, we'd have to have a complete track plan and a wiring diagram of how you wired the power from the TIU to the layout. How many TIU's? What version hardware and software do they have? How is the layout wired, is it conforming to the DCS star wiring recommendations? How large are the power districts? Are you running in passive or active mode with the TIU's? Where are the problems exactly, and what have you done to address them.

Those are only a handful of the many questions that come to mind with a large DCS layout. You really need to do some basic research on DCS and wiring practices to start and try to sort out what you have. We could spend countless hours suggesting things, and you could spent countless hours trying them out and not making any progress. I'm not sure you have any idea how complicated it can be to address such queries in an on-line forum with very limited information. Even with much more information, it's quite possible we still can't really address the issue.

If this were me, I'd start mapping the whole layout for signal strength using the same locomotive. I'd then examine the weak signal areas and see if they have anything in common. I'd also take my 'scope and actually measure the DCS signal around the layout to see if there's a pattern.


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