Why don't some DCC-ready locomotives like Tomix DC controllers?

[railsquid]

Here's something which has been vaguely puzzling me - I've got a small number of British and German N gauge locomotives bought new, all DCC-ready but unchipped (no DCC at Chez Railsquid). There's nothing wrong with them, but on the Tomix controller they don't run very well. More precisely they run, but all jerk into life at a low voltage and thereafter only run within a very limited speed range, no matter how the dial is turned; they will neither go at a crawl nor particularly fast.

 

Using a bog-standard Bachmann DC controller, they all run just fine.

 

This affects only a subset of my DCC-ready British/German locos; all others run as expected.

 

For the record, the affected locos are:

 - Fleischmann BR103

 - HobbyTrain BR110

 - Farish Class 40 (new version)

 

Anyone have any ideas why this might be happening? It's not a particular problem, just curious.

Edited January 25, 2019 by railsquid

[Gryphr]

I don't have a solution to the either, but it also happens with a new Fleischmann BR 101 using a Tomix Powerpack (N-DU101-CL to be specific). Other (also partly DCC-ready but older) german locos and trains run fine using it. Interestingly the same loco works perfectly fine with the Kato Powerpack SX which also uses PWM.

 

I would suspect it has something to do with the components on the dummy board innterfering with the specific frequency that Tomix uses for their PWM Powerpacks? Although that would mean that they changed something in the design of the boards in the recent years. I suppose inspecting the output of the Powerpacks and the components on the board could give some information though I neither have the knowledge nor the equipment for this.

[katoftw]

Are you using controllers with CL function?

[railsquid]

Nope, the Tomix controller in question is the N-600 "5507 TCS Power Unit" with just the DC feed connected.

[Sheffie]

I would be interested to see what a multimeter says if you connect it. Maybe the voltage or current is different between the two controllers, or between one of these locomotives and another that doesn’t have the same problem 

[railsquid]

So... new data point: with the V200 I acquired the other day, I initially assumed the thing in the DCC socket was a DCC chip, and replaced it with a simple blanking plate, i.e. one which just routes power between pins (which are the only type I've come across until now). With that it worked fine with my default Tomix controllers. As reported, I have determined that the "DCC blanking plate with DC gubbins", for want of a better description, actually works, it was just very loose. However, it does now show the same performance characteristics on Tomix controllers as the three mentioned above, while running just fine on the Bachmann controller.

 

Which leads me to suspect the other three locomotives will also contain similar "DCC blanking plate with DC gubbins".

 

However the "DCC blanking plate with DC gubbins" is evidently not just for decoration, as with a normal blanking plate only one pair of directional lights works.

 

Methinks I'll need to re-jig the controller set up so I can patch in the Bachmann controller when needed for these locos.

Edited January 27, 2019 by railsquid

[chadbag]

You can also just break down and go Digital :)

 

(And inherit a while new pile of issues)

[Yavianice]

PWM and digital operation was discussed by @kvp in this thread.

 

 

[railsquid]

1 hour ago, chadbag said:

You can also just break down and go Digital 🙂

 

(And inherit a while new pile of issues)

 

Yes, once upon a time, some four or so years ago, I was planning to go digital, then I fell victim to a disease known as "cheap 2nd hand rolling stock in excellent or easily fixable condition", most of which is non-DCC , and for the Japanese multiple units I'd probably end up spending more on decoders than the train itself cost, and the effort of manually converting each and every one is not something which seems an efficient use of my limited time, especially as with a bit of olde-style soldering I can solve most of the operational issues DCC would otherwise solve...

 

I might, at a future point in time, consider DCC for my British fleet, which is the only one which is reasonably DCC-ready.

 

In the meantime I welcome DCC for the slow but steady trickle of cheap "non-runners" which only need a bit of attention to the relationship between blanking plate and DCC socket 😉