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When my 4014 MTH Big Boy was acting up I got out my Signal Tester and learned four out of seven MTH 70' passenger cars kill the DCS TIU signal in my UP Steam excursion consist.  Why?

The cars are Vista Dome #7004 from Set 20-65116, Coach #5437 from Set 20-65116, Coach #5488 similar to #5437 (unknown MTH set or number), and Potrero Observation from Set 20-65227.  The first three were cataloged in 2007 probably and the Observation car in 2013.

What must be done to have these cars in my DCS consist?

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@Dillonm posted:

John does your led kit include the regulator or do I need order them as well?

 The Passenger Car LED Lighting Kit includes everything you need to light two cars, including the regulator boards.

@SteveMa posted:

I'm confused, are there only certain passenger cars that cause this impact that require modification?  

 Usually, it's circuitry in the car with capacitors across the power that degrade the DCS signal.  Without knowing specifics of the cars, it's hard to say why these cars affect the signal.

Truthfully, almost anything on the tracks has an effect on the DCS signal, some car and engine configurations just impact the signal worse than other configurations.

Last edited by gunrunnerjohn

Paul, I've never done a video, but I've posted a number of threads here on passenger car lighting with lots of pictures.  The actual process is pretty simple, but it is dependent on the specific make/model of passenger car.  Obviously, things like dome cars, multi-level cars, and observation cars with extra markers, taillights, or lighted drumheads require extra wiring.

I'm aware of no definitive list of passenger cars that degrade DCS signals.  If one exists, it's news to me.

The TIU Signal Tester used to identify the "trouble" cars was built from a kit designed by gunrunnerjohn and rtr12.  The tester is designed for use on the TIU output, not at the track.  It does give me a clue to the "trouble" passenger cars by removing all lighted cars from the consist (signal returned) and checking on track with consist one at a time and checking signal each time.  Three of the seven cars had no effect on the signal.  Four of the cars killed the signal.

I'll be interested in what you find that's different in the cars that kill the signal over the cars that don't.

FWIW, if I go to the trouble of opening the car up, it usually gets LED lighting.  For typical MTH Premier coaches, I can do one of those in 15 minutes, it's a really quick job.  It takes a little longer for dome, double decker cars, or observation cars with extra exterior lights.

This should not even be a question- by all means, upgrade to LED lighting! I upgraded my 10 K-Line Superliner cars to LEDs. Before, all 10 plus 2 MTH Genesis locomotives would draw almost 8 amps upon start-up- now with the LED conversions to the 10 cars, everything pulls 1.6 amps upon start-up, and I can run the train at 65 Scale MPH at 2.9 amps. Not to mention the awesome look LEDs have inside the cars vs. conventional lighting. And while you're at it, add some automotive tint to the window film of the cars.

The lighting does look much more realistic when it's evenly distributed instead of just a few bulbs.  Having the ability to adjust the intensity is a big plus as well, many factory cars look way too bright for me.

Did I forget to mention that the LED upgrade also eliminates the flickering of the lights?

Passenger car LED lighting (Again)

MTH Amtrak Superliner LED Upgrade in Pictures

MTH Premier Woodside LED Lighting Fix

LED Lighting Upgrade for MTH Full Dome Car

Is DCS signal loss as a result of incandescent bulbs new or is there something unique to the circuit board's of these MTH premier cars?  I recall the need for the inline choke but IIRC that was limited to passenger car incandescent to LED light conversions.  Also in the early years of DCS layout wiring and star pattern wiring troubleshooting, didn't the use of incandescents - either 1 bulb across the TIU output or the use of a lighted passenger car - improve signal quality?

@Susan Deats posted:

When my 4014 MTH Big Boy was acting up I got out my Signal Tester and learned four out of seven MTH 70' passenger cars kill the DCS TIU signal in my UP Steam excursion consist.  Why?

The cars are Vista Dome #7004 from Set 20-65116, Coach #5437 from Set 20-65116, Coach #5488 similar to #5437 (unknown MTH set or number), and Potrero Observation from Set 20-65227.  The first three were cataloged in 2007 probably and the Observation car in 2013.

What must be done to have these cars in my DCS consist?

First, I want to express my empathy for Susan.  This is a particularly bizarre and regrettable situation. 

But I just have to ask:  Does anyone else reading this thread feel gobsmacked?        

In what alternate universe do two products from the same company, ostensibly from the same engineering department, interfere with the workings of each other?  And more importantly, we blithely:

  1. Accept that as "normal"
  2. Discuss ways in which we (not them) can fix the problem

 

Sorry, but "dumbfounded" is too trivial a word for this situation.

If I had been responsible for such a situation, it's likely I would have died from shame and embarrassment by now.  Of course, the response from those responsible is "crickets".

George

Last edited by OGR CEO-PUBLISHER
@G3750 posted:

In what alternate universe do two products from the same company, ostensibly from the same engineering department, interfere with the workings of each other?  And more importantly, we blithely:

  1. Accept that as "normal"
  2. Discuss ways in which we (not them) can fix the problem

I tend to agree that there should probably be some sort of testing that goes on to avoid this situation - but that said, after the release of the Rev L. TIU and some of the issues with output drivers for the DCS signal getting damaged, it could be that there is a threshold at which the signal falls below a usable level.

Granted, the OP should be able to run the cars with any DCS engine she wants, but how do we know that her TIU is not in a degraded state and this just pushes it past the point of working correctly?

Like GRJ mentioned to - anything attached to the track is going to inflict some sort of change to the signal - that's the nature of electricity.  As an engineer, I know that changes to the impedance, capacitance, and inductance of the circuit will alter the signal and much of this happens in less than predictable ways depending on the gauge of wire used, the soundness of electrical contacts, and the quality of the track used (dirt, grime, rust, etc.).  And who hasn't heard the stories of people "blowing" on Nintendo game cartridges to make those work.

Lionel's use of an RF signal has some clear benefits here, but RF engineering comes with it's own set of caveats and challenges.  I can remember working on some RF circuits and a < 1mm movement of a piece of metal near the transmitter would alternately improve or destroy the signal completely - and I've on many occasions noted that I had to repeat a command on my TMCC remote owing to the fact that either the command base or the locomotive "missed" the command.  I think DCS problems are a little more apparent because of the two way communication and (I think) the default setting of the DCS remote to confirm response before letting the user continue (i.e. speed mode vs. "non-speed" (?) mode).  

Overall I think what we accept in this hobby for the money we pay is sort of ridiculous, on the other hand - these toys are little miracles in and of themselves sometimes.  When I was a kid - I remember playing with an Apple IIe and some early Lego motor control systems and thinking to myself - wow, what if I could this with my trains, but I never dreamed we'd get to this level of technology we are at now.  My biggest complaint about it is that TMCC and DCS are not really "open" standards.  We can't "roll are own" as they say.  I really look for some Arduino or Raspberry Pi solution to eat everyone's lunch soon - which will be a real boon to customers trying to keep their aging (and likely soon to be unsupported) command locomotives running.

Personally - I'd rather get models from the manufacturers that are high on detail, mechanically sound, with a motor, lighting, wiring, and a speaker that I could put my own electronics into.  I think it would actually benefit them to stay out of the electronics market - that kind of R&D is very specialized and costly.  Maybe I should switch to HO...

 

Nah... where's the fun in that!  Long live our 5ft prototype, sometimes scale, sometimes not, BIG, IMPRESSIVE, LOUD, SMOKE BILLOWING O gauge!

George, maybe that's why MTH is closing their doors.

John, if that is a contributing factor to that event, it certainly qualifies as a delayed (as in years) reaction.

Besides, it's never been my desire that MTH close their doors.  I just wanted them to get their engineering act together.  When they arrived on the scene, I had very high hopes for them.  In fact, many of my freight cars are made by MTH.  By and large, those hopes have been dashed.  But having them go away was never in anyone's interests - certainly not mine.

George

@G3750 posted:

John, if that is a contributing factor to that event, it certainly qualifies as a delayed (as in years) reaction.

Besides, it's never been my desire that MTH close their doors.  I just wanted them to get their engineering act together.  When they arrived on the scene, I had very high hopes for them.  In fact, many of my freight cars are made by MTH.  By and large, those hopes have been dashed.  But having them go away was never in anyone's interests - certainly not mine.

George

Your posted opinion of MTH lowers what I think of you. I have plenty of well engineered products from them that run great. They have run great for many years. So because of a lighted car that someone else posts about, you slam them? I'm getting very tired of your type posting here. Pile on the crap responses.

 You bought some MTH cars? WOW! Tell me more. I can't wait to hear all about them.

Care to discuss some other brands issues too? Bad wiring, bad boards, poor packaging, bad gears, etc. Slam away now. Don't hold back.

@Keystone posted:

Is DCS signal loss as a result of incandescent bulbs new or is there something unique to the circuit board's of these MTH premier cars?  I recall the need for the inline choke but IIRC that was limited to passenger car incandescent to LED light conversions.

There have been issues with incandescent lighted cars if they had a regulator circuit that placed capacitance across the rails.  I know a lot of passenger cars, not just MTH, have caused issues with DCS.  Many TMCC and Legacy locomotives will affect the DCS signal as well.  I've also seen some Atlas cars that just had incandescent lighting with no capacitors, etc. yet somehow they were nuking the DCS signal.  The 22uh choke fixed those as well.

It's really a simple fact, anything that has a low impedance to a 3.27mhz signal that is connected across the track power will reduce the DCS signal strength.  The fairly universal fix has always been to insert a 22uh (or higher value) choke in series with the power lead of the offending item.  This increases the impedance at 3.27mhz of that item to around 450 ohms + it's natural impedance and minimizes the impact on the DCS signal.

Susan, I have seen something similar to this happen with a second-hand passenger set I purchased about 2 years ago.  It turns out that the one of the previous owners installed some cheap LED retrofit bulbs that go directly into the socket.  While they were nice bright at almost all voltage levels, they were killers on the track signal.  After the removal of these bulbs, and the installation of a standard incandescent bulb, the problem was solved.

My dad has that very same UP Passenger set, and I'm not sure if his kills the track signal or not as. I will check it out and report back when I'm there this weekend.

I tested the same set of UP Passenger cars this weekend and didn't notice any problems with any of the cars degrading signal either by themselves or all together.  This was by method of the signal check feature on the Wifi App while running different PS2 & PS3 engines and with the passenger cars in motion behind the engines or parked on a siding.

I'd suspect that the passenger cars are not the issue but rather the amount of current needed to run the lights in those cars. Our Z4000 noted over three amps to run the whole set and nothing else on the track. If there is a severe voltage drop due to high current draw, that could be the issue, but this is only an educated guess at this point.

Last edited by H1000
@H1000 posted:

I'd suspect that the passenger cars are not the issue but rather the amount of current needed to run the lights in those cars. Our Z4000 noted over three amps to run the whole set and nothing else on the track. If there is a severe voltage drop due to high current draw, that could be the issue, but this is only an educated guess at this point.

I have the sense that Susan is reasonably well versed in the operation, have you looked at her website?  I'm pretty sure she would know if the power was overloaded.

Susan's Run Room

I have the sense that Susan is reasonably well versed in the operation, have you looked at her website?  I'm pretty sure she would know if the power was overloaded.

Susan's Run Room

Well? It happened to me.

....More than once.

( It's not "overloaded" for me but power dips or issues.)

I had some Aristo G scale switches fail and the signal went south. It only happened when more than one engine was drawing power. The wire under the switch corroded and wouldn't carry full power thru. Had to add wires jumping the switches.

I had a O scale passing siding fail and it only occurred in certain instances. I had to move the wires to the ends of the blocks (and maybe add some wires jumping switches?).

I had my original 2 rail layout wired with bulbs and some filters. I hadn't removed them all when I upgraded TIUs to version L. Worked at first and then went south.

An easy test for anyone would be to put them on an isolated test track and see what happens to the signal. Maybe something on the layout is corroded or not up to the task of carrying the full amp load the full distance???

I have the sense that Susan is reasonably well versed in the operation, have you looked at her website?  I'm pretty sure she would know if the power was overloaded.

Susan's Run Room

I've seen her website, It's very nice and descriptive. It's the only suggestion I can offer because the perfectly good set I have to test with does not exhibit this behavior unless her testing procedure with the TIU TESTER is giving her a false negative readout about the signal level.

 

I had the same issue with my Premier PS1 Blue Comet after Marty Fitzhenry converted it to PS3 for me. The track signal was perfect, until I put the cars behind it. I replaced all the bulbs in the cars with LEDs, and the problem was solved. I didn't really think much of it since the cars were made before DCS hit the market, and figured it was a necessary upgrade to make older equipment compatible with a new system. 

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