Available space has me looking to see if Z could be the scale of my future. As a way to test, I went out to my friendly neighborhood dealer (80 mile round trip) and purchased some Rokuhan track, a Microtrains SD-40 locomotive and an RC-03 train controller with an A023 AC adapter. All goes well with some track tacked to a piece of foam, but there's one thing that worries me. The locomotive runs great, but it keeps running (slowly) even when the throttle is brought down to zero. I have noticed this: The RC-03 input jack specifies 10V. The A028 supply puts out 12V. As an added conundrum, there are slots for 8 AA batteries in the controller (which add up to 12V). The thing is set up for 12V operation. I'd really like my locomotive to stop when I shut off the throttle. Any thoughts?
Do you have the "adjust ring" adjusted so that the speed control dial can be turned all the way down to its MINimum setting?
Yes, the adjusting ring is out of the way. The throttle goes all the way down to its MINimum setting. That's the first thing I checked.
The following video shows an RC-02 controller running an MTL SD-40 and the loco appears to come to a complete stop. I don't know how much difference there is between the design of the RC-02 and the RC-03. Can you exchange your RC-03 for an RC-02? Or, can you return your RC-03 and get a Micro-Trains modified MRC power pack? https://www.micro-trains.com/index.php?_route_=1300-mrc-power-pack-customized-for-z-scale-99513000
If you refer to my thread on the Marklin users group forum for small scale you will see a lot about this incompatibility with my new high efficiency motors ( Marklin calls them bell shaped armature). The Rokuhan controller puts out a small current at throttle stop with FWD/REV selected which turns the lights on with their trains but does not cause them to move. Except for their “shorty” locos which will move very slowly. With the new Marklin motors that tiny voltage has them moving rather fast, so no very slow running or smooth starts and stops with the RC02 or RC03 with those locos. It sounds like the same is true with the MTL loco you have. Also yes the Rokuhan AC power supply puts out 12V, that or batteries can be used but the same effect. Note that I have used 11.1V LiFe external batteries with the Rokuhan controllers. I did have issues with the Rokuhan controllers not reliably operating their turnouts (in pairs) with battery power. Not with AC power. I can only suggest the Snail Speed Controller as an alternative. I have not tried the Marklin controller or DCC.
And yes every loco is a bit different. I have one current production Marklin with the bell shaped armature motor that will sit at throttle stop. I contacted Rokuhan about this and they apologized for being unable to accommodate all other manufacturers locos with their products, very sweet and very Japanese answer! I suggested they consider a switch to disable the constant lighting feature in their controllers.
Point353, I find the video of the SD-40 interesting. I don't relish another 80 mile drive, but I might be in for one. I bought the RC-03 because it had two switch controllers built in, making it instantly outfitted to handle the two turnouts that I bought. Husafreak, the constant lighting feature is a bother. I had discounted that because the instructions that come with the unit tell you to use the "adjust ring" to stop the throttle from dropping to zero, thereby maintaining enough current to power the lights but not enough to turn the motor. The ring is not there to limit top speed. The implication from the instruction means (to me) that the throttle ought to go to zero voltage with the ring out of the way. It obviously doesn't. I appreciate your detailed comments, which are both interesting and instructive. I think you're on to something here.
Note that the RC-02 includes similar functionality to power constant lighting as the RC-03. Yet, the video seems to show that a MTL SD-40 will come to a complete stop when powered from an RC-02. If you do decide to try swapping the RC-03 for an RC-02, it might be advisable to bring your loco (and maybe some track) along with you to the shop so you can verify that the RC-02 will work satisfactorily with the MTL loco. http://www.rokuhan.com/english/products/RC-02 Train Controller, instruction manual.pdf http://www.rokuhan.com/english/products/RC-03 Train Controller, instruction manual.pdf
And husafreak’s video above shows the RC-02 behaving the same as my RC-03. These controllers have a problem.
The throttle stop ring is a bit misleading isn’t it? But note that with older Märklin locos with 5 pole motors it may be necessary to increase the throttle on the Rokuhan controller to the 12:00 position or more to get the loco to move. In this case the stop ring can be set to the 11:00 position and effect a convincing “constant lighting” feature for those locos. So these new high efficiency can motors have moved the bar for manufacturers. As newcomers to Z we have sort of stepped in at a difficult time. In Rokuhan defense one of the first locos I purchased was a Rokuhan DB181 and I love the way it runs and the constant lighting feature, just brilliant, so this new development is most unwelcome! I guess I would rather have an RC02 and a bunch of turnout switches that can be used separately if I decide on another controller than a RC03 although I have both. I think the new high efficiency motors are here to stay and controllers will change to keep pace.
I’m looking forward to the ride. I have 24x64 inches of space waiting to become an empire. I have an MRC 220 that I can wire into the tracks. It’ll go to zero voltage. I will have to stop the throttle though so that it stays below 12V. I also have an NEC Power Cab. I can convert the loco to DCC as cheaply as buying an RC02.
24x64 is big in Z world! The MRC sounds good. Eventually I am going to have to pick a controller I can use for all my stuff. I like the Snail speed controllers in operation but their "form factor" is too small. The version mounted in a panel maybe the way to go for me. Of course there is the Marklin controller but they are pricey. Since you say you are new to Z scale check out the buildings available in this scale. I was at a train show yesterday and there were no Z scale layouts, mostly HO. I really noticed (and my wife mentioned it too) that the bigger scale buildings just do not trick the eye the way Z scale ones do. But put some Z scale trains and buildings together and the realism is uncanny. Check out the layouts on the Rokuhan website for quick ideas and a sense of what track will fit. Beware of the really tight radius stuff though, that might limit your choice of trains.
I have a family history in B&O. I can remember as a child sitting in my great-uncle’s lap as he drove a B&O steam loco. In N, I concentrated on the last years of the Western Maryland and the associated roads—B&O and C&O—through Chessie, and finally the Maryland Midland, which uses old WM tracks. I understand that those roads won’t generally be available in Z. The SD40 is a CSX and I have a Chessie GP38-2 on order. It’s as close as I can come for now.
The following site has a test of various power packs, including the MRC Tech4 220. http://www.sumidacrossing.org/LayoutElectricity/ModelTrainPower/PowerPackTesting/ Measured peak output voltage is 19.3V, so 12V output would be reached at just above 60% rotation of the throttle. Note that the Micro-Trains modified MRC 1300 pack limits the output to only 10V, which would be at just above 50% on the Tech4 220.
I wired the MRC 220 controller to the Rokuhan tracks. Here's the result. Locomotive control is very smooth and easy. I did place a mechanical stop (a sticky pad for a chair foot) to the MRC throttle to prevent me from advancing it too much. Wide open, the MRC puts out more than 20V. The stop limits it to producing just 10V. Thanks all for your advice. I'm off and running in Z.
Micro-Trains has made Z scale models for B&O, C&O and WM. Finding some of them may be a bit of a challenge. Following are links to their database of locos and rolling stock. https://www.micro-trains.com/publicfiles/databases/zlocos.pdf https://www.micro-trains.com/publicfiles/databases/zdatabs.pdf American Z Line has also made some models for B&O and C&O, including a B&O steam loco. Again, locating them may require some effort. https://www.americanzline.com/locomotives/mikado/ https://www.americanzline.com/locomotives/emd-f3/ https://www.americanzline.com/locomotives/emd-gp-30/ https://www.americanzline.com/heavyweight-passenger/chesapeake-ohio/ https://www.americanzline.com/heavyweight-passenger/baltimore-ohio/ https://www.americanzline.com/lightweight-passenger/baltimore-ohio-2/
The Rokuhan Controllers with Constant Lighting can easily move a good running loco. The Controllers put out ~12 volt, o.5 uS pulses at a 25KHz rate (thats 25000 pulses a second). This similar to DCC Decoders output at 16 KHz, like Speed Step 1. See: AZL Forum post: http://www.azlforum.com/thread/1297/new-mtl-sd40-2-issue?page=2, about 20 posts down by Markm is a waveform: Rokuhan may have designed the motor board filters to filter these out. You could put a filter board in, like AZL has on their board or, a filter capacitor like marklin uses.
