Lionel SC-2 TMCC Controller - I didn't burn it up, but.....................................

[Buckeye Riveter]

After rewiring the layout, I am now running it with three (3) Lionel SC-2 Controllers, two of them are shown in the photo below.


You can readily see that the top controller is orientated different than the lower controller. The top SC-2 is controlling the switches on the layout, while the bottom SC-2 is controlling the accessories. The switches are powered from the track. The accessories are run from a auxiliary power pack, 14 volts.

Initially I mounted the bottom controller in the same position as the top with the wires entering from the left side. Until I mounted the bottom controller in the position shown it would not work. Now it works perfect as shown in the orientation pictured above..

It must be the antenna orientation inside the SC-2, but somehow the top SC-2 picks up the signal from the track switches it is controlling. Has anyone else ever heard of this? I found zero documentation in the Lionel instructions about the orientation of the controller. The mounting screws holes on the back are the only clue that I could see as to the possible orientation desired.[%-)][%-)][%-)][%-)][%-)][%-)][%-)][%-)]

The third controller, not pictured, is in the same orientation as the bottom controller and it works great, too!

I thought originally that I had burnt up the controller when it didn’t work. I reprogrammed it several time with no luck. It started working after I removed it from the backing board and it was just hanging by one screw close to the position shown. [%-)][%-)][%-)][%-)][%-)][%-)][%-)][%-)]

(For you new folks, an SC-2 Controller is part of the Lionel TMCC system and can control just about everything on your layout from lights to motors. I use them to turn the switches and turn on the oink-oink from the barn.)

[wrmcclellan]

Hey Buckeye!

A quick response before I have to leave for a Robotics demo I am chaparoning.

Just as you have the TMCC controller attached to your layout common (ground), do you have the common for the accessories transformer and SC2 also tied to the layout track common? TMCC uses the common as a conductive "antenna."

If not, the reorienting of the SC2s may have optimized them receiving leakage signal off the layout.

Later,
Roy

[Buckeye Riveter]

Roy, In fact the instructions say that the SC2 will be getting the signal from the track and the TMCC Controller. My SC2s are plugged into the wall via the small power pack that is included with the unit. They never discuss connecting it to the common ground.

After the reorientation, the SC2 just work flawlessly. The accessory controller will work when there is no power to the track. Of course the switch controller works, but the switches do not move.

If orientation makes this big of difference, WOW!

[Big_Boy_4005]

Buck, I don't use any of those, but when you mentioned antenna it makes me wonder.

I have some engines that work on my layout and others that don't. I took a couple of my "bad " engines up to the local dealer, and had him test them on his layout and they worked fine. Brought them home and zilch. I swore that one of them had a fried component, I could see and smell "burnt". That one used to work on my layout and slowly died.

This through the air stuff can be very quirky. In your case, even though the units are supposed to be the same, a slight variation may exist. How far away from the track can they be mounted and still work? Is there something shielding it from getting signal?

One thing you could do is run a wire off the track ground and bring it close to the SC-2.
Then there is also the issue of earth ground. Bring ing a source of that into the area may change things too.

[Buckeye Riveter]

Big Boy,
You know I opened those cases and looked inside the SC2s. [:)]They are the same. Like you, I thought I had burnt something to a crisp.

I couldn't believe it when it started operating perfectly in the position as shown in the photo. The third SC2 is out of the photo, two feet to the right and the orientation is the same as the bottom SC2 in the photo and it works perfect!

Obviously, I think it has something to with the signal and the orientation, but I have never seen anything that radio controlled so sensitive to direction. The third SC2 is running the 18v accessories. The one in the photo is running the 14v accessories. Needless to say, my Lionel Burning Switch Tower pours out the smoke with the 18v.

[Big_Boy_4005]

Well, at least you have it working.

I'm stuck with 5 different diesels that won't work, out of a fleet of 14.

One is known to be fried.
One has a mechanical problem with a motor (not TMCC related).
One that I mentioned, which works on the dealer's layout but not on mine anymore.
One which only works when I hold my hand over it.
And one cranky K-line which constantly stalls and shorts on switches.

That's over $1000 worth of locomotives that don't run worth crap.

I swear there are operating environment issues with TMCC. I wi***here were better ways to identify and fix these problems, but without being an electronics expert and having a scope, we just have to keep taking shots in the dark.

[Anonymous]

You mean like this:

http://www.lionel.com/products/productnavigator/InstructionManuals/70-0000-000.pdf


SC-2's try to pick up the signal from the track. The track signal doesn't propogate that far (picture a tube about 8" in diameter surrounding the track with the track dead center). If you move too far away from the "tube", signal fall off can be quite sharp and the SC-2 may not respond properly.

The ASC devices don't have receivers in them so they require the serial daisey chain wiring.

BTW, it is possible that the command base has started to "drift". If some of the loco's work and others don't but they will all work off of another command base it is possible that the unit needs to be adjusted. The adjustment isn't rocket science but it shouldn't be taken lightly. If you are not carefull you will wind up with NO loco's working.

[Big_Boy_4005]

I have considered getting another command base, partly to have a spare, and partly to see if things improve. Mine has very few hours on it, but is one of the first ones issued.

Lionel is so helpful with their suggestions. <heavy sarcasm> Not a single one of those problems describes any of my difficulties. I have no Powermasters.

For some people TMCC works fine out of the box. I have a very complicated layout, and have had a bunch of problems. Some have been solved, others have not. Some engines just don't want to receive the signal cleanly while others work perfectly. Of course, my layout's complexity could be part of the problem.

[Buckeye Riveter]

QUOTE: Originally posted by chuckn

You mean like this:

http://www.lionel.com/products/productnavigator/InstructionManuals/70-0000-000.pdf


SC-2's try to pick up the signal from the track. The track signal doesn't propogate that far (picture a tube about 8" in diameter surrounding the track with the track dead center). If you move too far away from the "tube", signal fall off can be quite sharp and the SC-2 may not respond properly.

Thanks for the link, but if you notice at the bottom it does not address the SC-2 Controller, but references the SC-1. SC-1 supposedly cannot take the higher voltages. Key word: Supposedly

My lower SC-2, that is now working perfectly, is 18" below the bottom of the track, so I'[m not sure I'm going buy the 8" argument. In fact, I have tested an SC-2 about 4 feet away from the track to see if it would just work plugged into the wall. The red light was flashing and it made the normal clicking sound. Inside the SC-2 there is an antenna much like inside the engines.

[wrmcclellan]

Buckeye,

I am back from the demo. Chuckin is right. TMCC signal is very low off the track. So it may be that the orientation would have been less critical if the lower unit was mounted at the same height below the layout as the top unit. Is the 3rd unit mounted high or low?

Big Boy

We had the same issues on our large and complicated club layout. Parallel tracks at different heights, metal bridges, tunnels, etc. The solution is to run extra ground wires from your layout common to either strengthen or shield the signals from each other.

TMCC runs at a very low frequency (455 kHz) and just like your AM car radio (100 kHz) dying when you go under a bridge or through a short tunnel, the TMCC signal does not propagate well through small holes or tunnels. If you have a metal bridge, tie it to the same earth ground as the TMCC wall transformer. Uneven parallel tracks may need a similar earth ground wire or mesh laid between the two tracks. You will have to experiment for best placement and effect. We also found that we had a bad connection to earth ground from the TMCC wall transformer. After doing all these things we resolved all our TMCC signal strength issues.

Also, if you used metal screen wire for plaster scenery, you may need to tie it to the TMCC wall transformer earth ground.

A quick way to know if you have TMCC signal strength (e.g. wall transformer ground problems, a metal bridge or tunnel) or TMCC signal interference issues (uneven parallel tracks) is to watch for headlight flickering when a TMCC command is being issued from the TMCC Command Base. Watch the RED LED on the Command Base, it will be synchronized with the headlight flickering.

Re your loco that works when you hold your hand over it. There is a grounding problem with the loco trucks or the loco's antenna is not working properly. If you look carefully at the newer diesels, Lionel has been adding extra ground wires from the trucks to the TMCC command board (where earlier units just use the truck to frame contact).

As Chuckn stated, the one that works at the shop and not at home may have a receiver drift problem. But I would also check its grounds and antenna connections.

Oh, BTW. We had another interesting problem with the club layout. It is in back of a hobby shop where they run TMCC on the demo layout. Guess what? Enough signal from the demo layout bled over to the club layout (30 feet away and through 2 walls) to mess up control on the club layout (and vice versa). We soon learned to turn off the demo layout TMCC when running the club layout. So if you are using a second TMCC unit elsewhere in your house, turn it off.

[ChiefEagles]

Buckeye, I'm sure glad you ahd color coded wires. [;)] Reading all of this is interesting. Trying to determine if I want AIU's or S2's. ????

[Big_Boy_4005]

Thanks Roy, I've only been playing with the earth ground so far, and that has helped a lot with some of the engines. It has worked well in my hidden yard with all of it's parallel tracks, and the helix with it's stacked tracks.

I haven't done any scenery, so that's not an issue yet, but I'm not planning to use any metal bridges or screen when I do. Scenery will be the last thing I do, and only after everything is working correctly.

I have been installing some chicken wire between decks to act as a shield, but I haven't gotten the mainline over to that section to try it yet.

I am trying to accumulate as much info as possible here in hopes of avoiding any more problems.

[wrmcclellan]

Elliot,

I should have added that the flickering headlight will be most prevalent in areas on the layout where there is a signal problem, so it helps you isolate the locale where the problem exists.

I will emphasize that the earth ground through your house wiring for the TMCC Wall Transformer causes more problems for most than anything else. So make sure it's ground is rock solid and that your house earth ground is indeed well grounded into earth via a metal water pipe or auxiliary ground rod (typically a 3/8 inch to 1/2 inch rigid copper rod that is 8+feet into the ground and is connected with a large gauge copper wire -#8 typ - to the ground bar in your electrical panel).

Regards,
Roy

[ChiefEagles]

Roy, just as a sideline. I have one big panel and it has the ground as well as bonded to power company. I have a subpanel in the garage/shop [100 amp service from house] with driven ground, "saw" shop [50 amp service from garage/shop] with driven ground, tractor/boat shed [30 amp service from saw shop] with driven ground and greenhouse [30 amp service from garage/shop] with driven ground. The only subpanel that does not have its own driven ground is the one I have done upstairs for the train room. Its only 20 feet of wire from the main panel and is bonded there. Now I know it is over kill when everything is bonded but, I like a driven ground at all subpanels. Why? Lightning and stray voltage will go to closest ground. Do not want it to "walk" back to the house's main panel.

[Anonymous]

page 4, paragraph 2 of the SC-2 owners manual:

"The SC-2 has a built-in antenna to receive
signals from the TrainMaster Command
Base. Place the SC-2 anywhere near track
connected to a Command Base, and it will
receive its commands."

The system can sometimes induce signals in nearby wiring. This has caused some repair techs problems when working on an engine near a live TMCC layout. The crystals in the Command Base and CAB-1 can be replaced (matched sets required) so that nearby layouts can function without interfering with each other.

[wrmcclellan]

Chuckn,

Yes on the crystals to prevent TMCC controllers talking to separate Command Bases from interfering with each other. But it stops there.

What you cannot change is the 455 kHz carrier that the Command Base uses to apply the TMCC signal to the track. It is this 455 kHz carrier that is sensitive to grounding due to its very long wavelength. TMCC receivers in the locos are 455 kHz receivers. If one ever changed the 455 kHz, you would have to change all your TMCC receivers in your locos and accessories.

So two TMCC Command Bases with different crystals (27 Mhz region) still step on each other because the biggest antennas, the layout commons, are both radiating the same 455 kHz frequency signal.

TMCC uses 27 MHz only for the link between the CAB-1 and the TMCC Command Base. The 27 MHz does not go to the locos.

The Command Base receives the 27 Mhz commands from the CAB-1 and then remodulates (apparenty using bi-phase shift keying - BPSK - I looked at this with a digital recording oscilloscope a couple of years ago) the signal onto a 455 kHz carrier to inject onto the track.

So changing crystals in CAB-1s and Command Bases unfortunately does not help.

Regards,
Roy

[Anonymous]

Interesting Roy, the "advanced" TMCC manual recommends this to avoid intereference. They were only talking about preventing cross over from CAB-'s to the command bases, e.g. from one neighbors layout to anothers. If the layouts are physically too close together, the signals will jump track to track from inductive effects?

[Big_Boy_4005]

I'm 99% sure the house wiring is not the problem. I wired the entire house myself from scratch, six years ago when I built it. The system has all the modern grounding features with ground stakes and water pipe bonds. The outlets are as good as they are going to get.

My command base is not in it's final location, I'll be doing that move fairly soon to get things settled and debugged. As it sits, it may be too close to the power supply, which doesn't help the whole process.

[wrmcclellan]

Chuckn,

Yes. For two layouts (and the larger the layout the worse the problem as the amount of common rail lengthens the 455 kHz antenna gets more efficient), the radiation from one will couple into the other.

Once I understood the transmission mechanisms, changing crystals made no sense other than an attempt to minimize collisions on the 27 Mhz interface between the CAB-1 and the Command Base. I think the main reason to change crystals would be to avoid interference from other 27 Mhz devices one might own (i.e. RC cars).

One cannot really add a second command base to one's layout. The unmodulated 455 kHz signal is a "keep alive" signal to all the TMCC equipped locos and accessories. This is how your TMCC locos decide whether to act in conventional mode or not. If the 455 kHz carrier is present (note you do not have to touch your CAB-1 when you turn on your layout for a loco to recognize the TMCC signal as long as the Command Base is powered and attached to the layout common), your locos come up in Command Mode. No 455 kHz carrier, then the locos come up in conventional mode. If you were to add a second Command Base without synchronization (phasing) of the two 455 kHz carriers, they will actually slowly drift in and out of phase with the TMCC signal cancelling itself when they are out of phase. Not a pretty thought. Many have experienced the loss of TMCC signal to have the loco change to conventional and with 18 volts to the track cause it to rocket into layout orbit (i.e. the floor - thus only the Chief is protected from serious damage since his locos do not have far to fall [}:)]).

Elliot - sounds good regarding your grounding. Since you have had some problems I would double check how secure (the house wiring side) ground wire is attached to the outlet where the Wall Transformer is plugged in. If you are using an extension cord, make sure the ground is in good shape (this was the final problem on our club layout - the ground wire in an extension cord was loose). I have read rumors about some surge protected outlet strips causing a TMCC ground problem although I cannot think of any technical reason for this.

Regards,
Roy

[Buckeye Riveter]

QUOTE: Originally posted by wrmcclellan

Buckeye,

I am back from the demo. Chuckin is right. TMCC signal is very low off the track. So it may be that the orientation would have been less critical if the lower unit was mounted at the same height below the layout as the top unit. Is the 3rd unit mounted high or low?

The 3rd SC-2 is mounted high and at the same orientation as the lower SC-2. It works just as good as the one mounted lower at the same orientation. Is the signal coming from the track, even when the track power is off? Both SC-2s work with the track power off. The upper SC-2 does not work with the track power off because the switches run off of track power.

Chief, if you will look real closely you will see the color coded wire for the switches. It really simplified the switch wiring.

[wrmcclellan]

Buckeye,

If the TMCC Command Base is powered and the track power is OFF, the other TMCC units such as the SC2s (since they have their own power) will work.

The TMCC signal is being injected onto the layout common rail. It does not matter whether the track is powered or not.

To be clear - Yes, the SC2 is listening to the 455 kHz signal from the track.

[Anonymous]

Signal is carried on the outside rails by way of the "U" terminal. So long as the command base is powered up, the signal is being propogated. If you have all the commons tied together the signal could try to follow/propogate along these wires.

[Anonymous]

Any bridges or wire screens for mountains, etc should be isolated from track common and tied to utility ground through a .01uf 1000V capacitor. The .01uf 1000V capacitor grounds the objects with respect to the 455 KHz signal while blocking the 60 Hz power (minimizes danger of shock). The utility ground connection is best made at the same outlets that the command base is plugged into.

Daniel Lang

[daan]

Just something out of the RC car world regarding engines that don't work. Sometimes it helps to relocate the antenna inside the vehicle or add metal things to it. Like the handrails mentioned in the CTT. The antenna must be of sufficient length to recieve a signal because it should be trimmed to fit the wavelength of your signal. In RC when you cut the antenna wire from the reciever somewhere (make it shorter) the unit won't work at all or the area where signals are recieved is much smaller.
Also when you have a track crossing over another track with a huge length of rails between the under and upper level, signals will interfere, since the signal of the upper track is not "lined up" with the signal on the lower track.
I guess you could find solutions for receiver problems also on radio control forums.
The setting of the sender-wavelength is also giving a lot of RC car problems, but to get them tuned you should be carefull, though it are only a few potmeters you have to set in a different location, it is the trick to get it exact on the right place, otherwise you indeed end up with nothing working at all.
By the way, mobile phone antenna's , TV antenna's (sender), power lines, lightning and anything else (even an ungrounded wash dryer) can cause that radio control doesn't work as it's supposed to.

By the way, I think it's a very sad thing having to accept that 5 locomotives don't work..

[wrmcclellan]

Daniel points out a huge error I made in my earlier posts. I meant to say to tie the wires used to isolate tracks and any screen wire or metal stuctures to earth ground. It has been a long time since I dealt with this issue and I forgot where the connection was made.

Thanks to Mr. Long for pointing it out. I will edit my posts to correct them.

Also as Daniel points out - please be careful about tying layout elements to ground if you dod not understand your house wiring. We do not wish for anyone to get shocked or worse.

Regards,
Roy

[Buckeye Riveter]

If the track acts as an antenna, does the wiring from the transformer to the track also act as an antenna? The way my layout is wired I might have made a big antenna just from the hook up wiring.[:D]