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I have a Lionel SC-2 and I've been fighting TMCC signal issue. Basically plugging the thing in normally, some switches switch one way, but not the other way.  I don't think it's broken because if I plug in with the wall-wart and move it around to just the right spot, sometimes I can get it to work for both directions on Switch 1, but it's still finicky. and this isn't a place I can mount it permanently.

I've tried various things, I cut the trace, as was suggested here, and powered it directly with the U of the base connect to the unit, and the.  I tried putting some metal tape under the layout above the SC2 and connecting that to earth ground. (Using metal tape under overhead passageways and grounding this has helped me with locomotives with TMCC signal issues.)

I think it's the 'TMCC ground plane issue' as is discussed here, but for the life of me, I'm unable to find a way to make this function properly.

The layout isn't  that big, maybe 6x10 feet or so, it does have a rats nest of wires beneath with power going everywhere.  Maybe I have too complex a wiring system underneath I wonder?  The switches are powered with a second AC Transformer, though I still have trouble with the SC2 even with no switches at all wired to it.

Any suggestions here?  TMCC for locomotives mostly works pretty good though I have a few dead spots here and there.

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@BillYo414 posted:

Maybe some chicken wire stapled under your layout?

You want to be somewhat circumspect in how you address this issue, you can make a bad situation worse with the wrong configuration of earth ground or too much coupling between earth ground and the tracks.  One of the major contributors to weak TMCC/Legacy signals is too much capacitance between the earth ground and the track.  This really comes up with really large layouts with thousands of feet of track, places like the NJ-HR layout deal with that issue.

@BillYo414 posted:

Are you using anything to conduct the plane? I'm new to this stuff but if I follow what you're saying, it sounds like your ground plane needs some work. Maybe some chicken wire stapled under your layout?

What I have been using so far for tracks is I take metal tape that's used for heating and sheet metal work, and I tape it below all the raised tracks. I connect all this metal tape together mostly by taping on top of tape, but some places have wires.  This doesn't work by itself, but what fixes the situation for trains is grounding that metal tape to the 3rd prong of the wall outlet. I have an actual degree in EE, but I have zero idea what's going on here myself really.

Honest, I thought I figured this out, and tried a similar thing under the track, of putting metal tape under the layout, and then putting the SC-2 below that with various combinations of wires from the U pin connected to the SC-2 or with wires beneath it, and nothing helps.

I do see posts here in this forum where people declare that it's not a ground plane, and that something else is going on, but mostly they're talking down the official Lionel explanation and I have yet to see someone really say what's going on here.

I wish I could just modify this SC-2 to be honest, and wire it in directly and rip out the antenna, but not sure if that's possible.  I have a PowerMaster that's connected right by it that basic works perfectly no problem.  The whole TMCC signal thing is pretty confusing, especially coming into a layout that's already built.

What I have been using so far for tracks is I take metal tape that's used for heating and sheet metal work, and I tape it below all the raised tracks. I connect all this metal tape together mostly by taping on top of tape, but some places have wires.  This doesn't work by itself, but what fixes the situation for trains is grounding that metal tape to the 3rd prong of the wall outlet. I have an actual degree in EE, but I have zero idea what's going on here myself really.

Here's an excellent treatment by the late Dale Manquen, one of the best coverages of the TMCC signal basics I've seen, and better than I would explain it.  It will also save me a ton of typing.

TMCC Signal Basics by Dale Manquen.pdf

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Cathryn:

found this on another SC-2 post. don't know if it has anything to do with your issue but thought I would paste it here.

The SC-2 needs to receive a signal from the house wiring ground. An easy test is  to temporarily lay a three wire extension cord next to the SC-2. The extension cord must be plug  ged into a three prong outlet. The Cab-1 does not talk directly to the. SC-2. Placing your hand next to the SC-2 will let see a stronger signal also. If this experiment improves operation, a permanent solution would be to install a ground wire near the SC-2.

I have a similar size layout, also a wire rats nest, no problem with (3) sc-2's. here's my wiring environment:

-powering them with their wall warts connected to a power strip with heavy duty extension coiled on the floor approx 4' from the SC-2's.

- to power the switches, a Powerhouse connected to a ZW-C (in your environment would be the Powerhouse connected to the Powermaster)  is connected to the same power strip with heavy duty extension cord coiled on the floor.

- my track is powered by (4) PowerHouses, (4) PowerMasters and (1) Command Base. The Command Base along with each of the PowerMaster Common (U)  terminals are connected to the common (U) of the ZW-C (in your case Powermaster) is connected to the common (U) of each of the Powermasters.  These ( Powerhouses , PowerMasters and Command base are connected to another  power strip with heavy duty cord plugged into the same duplex wall outlet along with the power strip supplying the SC-2 and switch power.

Cathryn, your environment is similar to mine so it should work. after checking all the physical connections  of the SC2-2's to the switch motors, that you have a common (u) for everything tied together, Cab1/2 antenna extended,  a different wall outlet? sorry for the scatterbrain approach. I have been there many times myself, but ultimately find the solution, slapping my forehead in disbelief.

All the best!



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