Having some unexpected issues with my first DCC installation...

Model Railroader Electronics and DCC
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I’m currently building a Bowser A-5 (PRR 0-4-0) for a friend, who operates with DCC. He’s given me a NCE D13SR decoder (non-sound), and the instructions, at least for my input, seem very easy to follow.

I’ve isolated the motor, and have added all-wheel pick-up to both the loco and tender. To simplify the wiring, I’ve placed the insulated tender wheels on the same side as those of the locomotive, and have installed a split piece of copper-clad circuit board in the tender, with wires from the tender trucks soldered to their appropiate sides of the board.
Because of the drawbar connection point, I didn’t use the supplied six-prong plug between the loco and tender, instead substituting a pair of three prong connectors, one on each side of the drawbar.

I haven’t yet done the final wiring connections for the head- and back-up lights

Here’s the all-wheel pick-up on the locomotive…

…and on the tender…

Here’s the split copper-clad board for current collection. The four wires coming up through the floor of the tender are from the wheel wipers on the tender trucks, while the two looped black wires to the right are from the loco’s wipers.
The straight red and black wires are, respectively, for the right and left rail power pick-ups, and lead to the decoder, as per the diagram on the decoder instructions…

Here’s the partially hooked-up decoder…

…with the orange and grey wires connected to the outboard pins of the mini-plugs - with the loco plugged-in, they lead to the

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Hmmm…I wonder if the decoder is set so DC is active?

I will usually wire up the these old locos without a decoder first, temporarily jumping the red and orange leads and the black and gray leads in the tender, then test it on DC to make sure I don’t have any shorts. Then I install the decoder. I program the decoder and set it to DC active, then test on DC, then DCC. I usually tweak the programming and set it to DCC only then.

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Wayne

Your work is outstanding!!! Great way for all wheel power pickup. I’m not familiar with the NCE decoder so I can’t help you on that.

I’ll send you a PM with my personal email, I would like to ask you some questions about the particularities on the copper clad boards.

As you are not into DCC was the decoder programmed when you received it?

Mel

My Model Railroad

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If it came out of the package configured for DCC only, it wouldn;t run in either direction on DC.

Which DC power pack are you using? Decoders can be confused by the fancier PWM power packs, as the PWM sort of looks like the DCC signal.

Otherwise - it might just be a dead motor drive on the decoder. It may have been DOA, but it also takes just a brief touch of the track power to the motor wires to fry the output of a decoder.

–Randy

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Not to my knowledge, Mel, and the package was sealed when it was given to me. I asked my friend about programming it, since he knew that I didn’t have the capablity to do so. He said that if I didn’t feel up to installing the decoder, he didn’t mind doing it, but after I read the very clear instructions, didn’t think that it looked complicated at all.

I’ve re-checked all of the wiring to make sure everything was done properly. However, I am not sure about the motor connections: the instructions show the grey wire to the “-” terminal on the motor and the orange wire to the “+”, but neither are marked and I’ve never been aware of them being plus or minus other than they alternate (on DC, at least) when I flip the direction toggle.

I’ve read that there should be a resistor in each of the light circuits and I have some 1K 1/4 W ones on-hand. I plan to put them in the white (headlight) and yellow (back-up light) wires, but am wondering if they get hot in operation. I’d prefer to keep them in the cast-metal tender, but I’ve lined it completely with sheet styrene.

Wayne

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The power supply is a ControlMaster 20, and I use it with a Stapleton Electronics Varipulse Model 821A. I does put out PWM current.

The decoder instructions note that it should be tested on regular DC and “driven by a good quality smooth DC power unit.” It also specifically recommends not using pulse power.

With the decoder not connected, the loco runs as it should, in both directions.

EDIT: I just now tried it using the MRC controller and it will run in reverse, but not run forward at all (or in reverse, like the PWM throttle, when set for “forward”). There’s also a lag in starting, despite the momentum not being activated.
The momentum feature on that throttle never worked - when activated, any loco being used would sit for several seconds, then take-off like an old Athearn rubberband-drive.

Wayne

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I’d say you got it correct, then. Finish up the install and let your friend try it. I don’t believe the resistors get very warm, so they’ll be fine in the tender.

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If you are using LEDs for the lioghts, then the 1K resistor is the right choice, and they won’t get warm at all.

–Randy

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Hi there. Engines running in only one direction can be a sign of a short or a motor not totally insulated from the frame. I would use an ohm meter to check. Can it run in both directions with the boiler removed? Sometimes things touch when the boiler is on.

Simon

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Thanks for that info, Randy. I’m pretty-much in the dark with any wiring beyond motor hook-up.

Thanks for your suggestion, Simon.

I have very little knowledge of such electrical stuff, but did remove the connector from the upper terminal to the motor case before beginning the DCC installation. The motor sits within two cast metal blocks, the front one being the gearbox, and the rear one simply a mounting device and counterbalance to the weight of the gearbox. The frame is, of course, metal, too…

I tried running the loco with the boiler removed (a bit awkward due to the wires for the headlight - I’ll cut them and install mini-plugs inside the boiler, as it will make routine maintenance easier for the owner) and it ran in the same manner - in reverse only, regardless of the direction switch on the controller.
The connections to the motor are covered with heat-shrink tubing, so there’s no contact there.
My meter showed zero resistance at all three settings, but I’m not sure if that’s a good or bad sign.

Another friend, currently out of the hobby, always wanted lights in his steam locomotives when I was doing a lot of re-motoring for him - a lot of brass locomotives with open frame motors literally worn-out from constant running. Installing the can motors was easy enough, but building circuit boards for directional lighting, along with the wiring, made the models difficult to handle when painting them. They usually turned out well-enough, but were a pain in the posterior with which to work, hence my personal

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Strange… how did you connect the motor to the frame, with silicone? Some motors have insulated covers, others not. You also might have a faulty decoder, but that is unlikely.

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The motor is held in place by both the gearbox and the cast metal block at the rear of the motor. I actually followed a post by a fellow modeller on my home forum, who built the same loco, and also installed DCC. I’ve done basically what he did, as I was well aware that this was an area in which I needed some guidance.

Wayne

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As another test, I would disconnect the motor leads from the decoder and use a 9V battery to test motor. Hookup wires to see which way wheels turn. Reverse wires to battery to see if wheels run opposite ways. If this works, then I say a bad decoder. If not, bad motor? Joe

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Before the decoder was added, the loco ran normally on DC power from the track, and if I unplug the tender (including the decoder therein), I can run the loco with jumper cables from the track or from the transformer in my shop, simply connecting the jumpers to the motor pins on the plugs between the loco and tender.

Wayne

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The motor he used probably had an insulated cover, preventing a short. Your motor’s cover might not be insulated, which means that the contact with the frame might be creating a short. You can test it with an ohm meter. If there is contact, you can use silicone or kapton tape to isolate the motor from the frame.

Simon

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I’d agree, but his kit and mine were the same…same locomotive, same detail package, and same motor. If the cover wasn’t insulated, I don’t think that it would have run using DC, either.
I could put tape under the motor, but its end-bearing housings, also metal, fit into the metal gearbox and the metal block to the rear, and both are screwed to the frame.

I just now did a couple of tests on the track in my workshop. It’s powered by an old Scintilla power pack dating from the mid-'50s. Its “Off” position leaks some current to the track, so not a very sophisticated piece of technology.

With the loco on the track without the tender, touching the plug pins for the motor to their respective rails, the loco will run, and will respond to the direction switch as it should - it goes forward when the switch is so-set and likewise in reverse.

I then put the tender on the track, and plugged the loco’s connectors into the ones on the tender, placing the decoder between the current pick-ups and the motor.
Applying power, the loco moved forward as dictated by the direction switch, and then, with the switch reversed, the loco also moved in reverse.

Thanks, Randy! It appears that you’ve given the proper solution, while I thought that the PWM throttle used on the layout would be more compatible with the decoder, seeing as the normal DCC output is also PWM.

Thank you all for your responses…I was embarrassed to think that I had screwed-up badly for a good friend, even though I know that he c

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Glad it worked out!