Lionel Legacy and MTH DCS Not Working Together

Do you have the TIU/Legacy cable connected?

Yes I do have the cable connected.

Howdy Nick,

I believe I presented my solution to you on an earlier thread of yours.  It went something like this: 

I gotta tell ya, I purchased one of the MTH TMCC/DCS cables and I was going to connect my LIONEL Base 1-L to the DCS so I could run my LionMaster Conrail SD80MAC equipped with the LEGACY Control System through the TIU using the DCS Remote exclusively.  Well, I chose to connect the Base 1-L directly to my terminal block, (using 18 gauge wire from the "U" post on the Base 1-L to the negative side of the terminal block) and control the Legacy engine with the Cab 1-L instead of using the DCS Remote.  I have been able to run both the Lionel Legacy and MTH Proto2 and Proto3 Engines simultaneously using the Cab 1-L for the Legacy engine and the DCS Remote for the MTH engines .  They work GREAT together without any conflicts so far.  I am using the "Star" wiring technique as described in Barry's book.  If you don't already have the book, get it.  It's worth its weight in gold.  Just my 2 cents, your mileage may vary.

Chief Bob (Retired)

Thank you for the suggestion, I will definitely check that out, thanks! 

We've never had that problem and we've been using DCS with TMCC (and later Legacy) since early April 2002. We connect the Common connection from the Legacy base to the Fixed Channel 1 INPUT side common on the nearest TIU. Connecting on the output of a TIU is a crap-shoot because the common connections on newer TIU's aren't tied together. On the input side, usually the transformer is connected at least to Fixed channel 1 and in multi-channel implementations you almost have to tie the commons together to properly ground the layout.

What WILL kill a DCS signal is certain lighted passenger cars and cabooses that had some older light-board circuits. The fix for those was putting choke coils on the leads from the pickup rollers to the lighting circuit which filters out the pulsing from the lighting circuits.

Thanks for the reply, I will try your solution.

Matt,

We connect the Common connection from the Legacy base to the Fixed Channel 1 INPUT side common on the nearest TIU. Connecting on the output of a TIU is a crap-shoot because the common connections on newer TIU's aren't tied together. On the input side, usually the transformer is connected at least to Fixed channel 1 and in multi-channel implementations you almost have to tie the commons together to properly ground the layout 

Actually, the best way is to connect the Legacy or TMCC base either directly to the track or, alternatively, all of the OUTPUT Commons of all TIUs. It's always best not to pass the DCS signal through thee TIU signal generators.

What WILL kill a DCS signal is certain lighted passenger cars and cabooses that had some older light-board circuits. The fix for those was putting choke coils on the leads from the pickup rollers to the lighting circuit which filters out the pulsing from the lighting circuits.

Add to this list some, but not all, Legacy and TMCC engines. They will also degrade  the DCS signal. I suspect that this may be the source of Nick's problem.

I control MTH with DCS and Lionel with Legacy. I don't use the MTH #50-1032 cable to connect the TIU to the Legacy base. You only need that cable if you want to control Legacy/TMCC engines with your DCS remote. I have the cable, but have never tried using it.

I wired my layout for DCS as close as possible to the guidelines in Barry's book (above). I had DCS for a few years before adding Legacy. When I got the Legacy system I connected the Legacy signal wire to the output common (black) terminals of my TIU and jumpered all of the TIU common terminals together. I have no problems with either DCS or Legacy, everything works very well. This is the best layout I have ever had as far as everything (Legacy/DCS) working without problems.

Just a passing thought here, but in what order do you turn things on when you power everything up? I have everything (DCS, Legacy, track & accessories) powered by one power strip and it is all turned on at the same time. I have several spurs to park engines that are on toggle switches. The MTH engines do as you say when I turn on one of the sidings after the layout is all up and running.  

I also recommend Barry's book, lots of good info in there that you will refer to time and again. It covers a lot of ground (no pun intended).

I believe I have pin-pointed the problem to my Legacy SD70ACE, it seems to cause the bad behavior to MTH engines. Do I just splice in the choke onto the pickup wire?

Nick,

 Do I just splice in the choke onto the pickup wire?

Yes.

Place it in-line between just after the pickup roller are connected together, and the engine's electronics.