Odd behavior: switching mode vs transformer

A "switching mode power supply" is usually a DC voltage so I'm guessing your Lionel system puts DC voltage on the track.  The Z-500 puts AC voltage to the track.  DC voltage can have either positive or negative polarity...whereas AC voltage alternates between positive and negative polarity.

The main cabin lighting of every MTH car I've seen uses regular incandescent bulbs which operate on AC or either polarity of DC.  However some of the smaller lights in these cars use so-called LEDs (Light-Emitting-Diodes) which are wired such that only one of the two DC polarities will work; since AC provides both polarities, AC works to light up these LEDs.  My guess is your DC track voltage is the wrong polarity.

Surely you're not the first to run into this and I'm sure you'll have a solution or workaround shortly.

Hi Stan,

Thanks for the explanation.  That makes perfect sense.  So, I have a 9-volt AC-to-DC BOSS power supply for powering guitar effects.  The pin inside the cylindrical plug is ground, while the outside shield is positive. Without it in hand, I'm 99% sure that this is the reverse of the Lionel switching mode power supply's plug.  Assuming that the diameter of the Lionel and BOSS power supply plugs are the same, can I safety test this theory by plugging in the 9-volt power unit? It seems like it should be OK. Boy, so glad that I didn't return the model for a refund, as this was the last one I could find. MTH did a really great job on this one.

Thanks again,

Tomlinson Run RR

Since you confirmed the Lionel supply is DC, I think that explains the behavior.  To test the theory, I'd think you want to isolate the MTH car.  To that end, how about simply taking the cylindrical plug and touching the outside shield to the MTH car wheel while using a short piece of wire or an unbent paper clip to momentarily connect power from the inside of the plug to the center-power-roller on the car.  Then do the reverse (shield to center-power-roller, and paper-clip to wheel).

Your Lionchief Lionel set, in addition to running on the supplied DC power supply, will work just as intended on 18 volts AC also.

If you power the set with your Z-500, it will function perfectly and the MTH caboose will function as designed too.

Stan,

I tried the "reversed" DC power supply test as you suggested and the lantern LEDs lit up.  So your DC polarity explanation is confirmed and a paper clip will now be part of my troubleshooting tools :-).  

Rob, thanks, yes I figured that I could use the MTH 18 V transformer with the Lionel track. Unfortunately, the MTH transformer output plug is too large for the Lionel terminal track.  I figure I can get it to work if I buy the Lionel terminal track with wires and keep the MTH transformer plugged into the DCS Remote Commander. The commander unit provides the two output wires needed to attach to the terminal track. But that's an awful lot of clutter to trade for two tiny lights.  Maybe someday when my layout isn't on the living room floor? I liked the elegance of the Lionel power supply but clearly there was a slight trade off with this particular caboose model.

Thanks to you both for the suggestions and information. It was helpful.

Tomlinson Run RR

The terminal track is nothing special except for a little notch in the roadbed. Almost all FasTrack sections have the connectors underneath - turn them over and have a look.

You can connect to the outside & center rails any way you wish, in addition to making up your own leads with .110 female quick connectors.

Yeah, I wondered if it was possible to bypass the existing terminal post as I had done a simple test with alligator clips to the end pins with my AC transformer yesterday.  Will give it a try when I've got more time. Thanks For the tip!

If I understand this option, the DCS Remote Commander is simply being used an an adapter from Z-500 barrel plug to 2-wires?  If so, you can get an adapter for less than $1 with free shipping on eBay (search "5.5mm female adapter") though it takes a few weeks to get it from Asia.  Here's the idea shown with the power-plug from my MTH Z-transformer brick...

Yes, exactly.  Sweet! And you can't beat that price.

Thanks.

OK, so here's how I got my MTH transformer, DCS Remote Commander, and etc. working with my Lionel track, which was formerly powered by DC. This means that I can now use my MTH Pennsy cabin car with the reversed polarity LEDs and enjoy their lovely glow on the track that I prefer.

I decided against the female connectors, although I had some on hand, just because I didn't want wires running under the track.  This is a carpet layout after all. So, instead I bought a Philmore 6-foot DC Plug Cable Assembly, No. TC258, inside dia. 2.55 mm, outside dia. 5.5 mm, straight plug, 18 AWG. It fits the Lionel Terminal FasTrack perfectly and makes for a nice smooth looking connection.  I got two spade terminals to attach to the DCS Remote Commander gizmo, which in turn goes to the transformer.  The parts cost a little more than what stan2004 proposed but I wanted to buy from a store where I could ask dumb questions and establish a rapport since this is my first adaptation project.

After some challenges with my hardware store "quality" crimping tool, pathetic hand grip and several wasted connectors later, the very nice electronic shop owner (Electronics Plus, Littleton, Mass.) used his serious-business crimping tool on them, and ended up soldering the two connectors for me 'cause it was handy and he is a very nice guy.

I got my new adapter home, hooked it up, and as we say in my line of business, "it just worked".  I was able to power my diesel up on a test track section, put it through its paces, and shut it down.  Yeah! Here are some pix, although it's hard to tell that the cab lights are powered on, but they are. Now enough distractions and back to school work!

Thanks for your suggestions guys.

Tomlinson Run RR