So I'm going to be putting DCC in the remainder of my locos that don't have it. I'd prefer to wire in a connector of some kind and let the decoder be removable.
Which standard should I install in my locos? It seems like 21MTC is becoming the standard quickly, but it seems like NMRA is or maybe up to recently was pushing the PLuX standard.
ESU sells a baseboard (link: ESU 51967) that you can wire into a loco that gives a 21MTC (21-pin) connector.
Considering I'd like to add sound to every loco I own at some point, this seems like a good path.
Can anyone tell me why I should not do this, or any pitfalls I may encounter if I go this route? It does seem sub-optimal with regard to cramped interiors like that of my Bachmann Spectrum GP30.
Julian
Modeling Pre-WP merger UP (1974-81)
The only issue with the 21 pin at this time is that some US manufacturers, like TCS< are using the pins differently than the Europeans like ESU, in terms of the additional function outputs. The Euro version uses logic level outputs for the upper functions and the 21 pin motherboard has the drivers on it to actually run things like LEDs. TCS's version outputs full power function drive for all functions.
You can see this in action if you look at some of the Loksound Select decoders - the Select Direct is basically a Select Micro on a larger board, connected via the 21 pin interface. The Euro style makes more sense, you only add the extra (relatively large) drivers when using more functions, for fewer functions you just leave off those parts and use what's on the decoder. Hopefully the NMRA will get its act together and adjust to the Euro style. The 21 pin is pretty much the way forward, it's smaller than the 8 or 9 pin connectors yet has plenty of connectiosn for motor, track, functions, speakers, and keep alive. Sound decoders with 9 pin usually have a second conenctor for the speaker and capacitor and chuff sensor, and even then still have solder pads for extra functions. 21MTC eliminates the need for soldering wires and having multiple connectors.
This pretty much covers it all:
http://www.sbs4dcc.com/tutorialstipstricks/21mtcconnector.html
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
TCS has a similar approach. They have 4 styles of mother boards you add 1 of their sound or non sound 21 pin decoder to. Joe
http://www.tcsdcc.com/
The Loksound Select Direct doesn't use the 21 pin interface, but rather the Next18 .... just to add some more confusion !
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Their is a problem when standards no longer are standards. Now it seems everyone is going in different directions, kinda like it was in the beginning of DCC.
Put what fits in your particular locomotive. You may save a marginal amount of time wiring when you go to add sound if you standardize your harness, but depending on how long you wait to put sound in you may find that your harness is obsolete, or not supported by that brand new super miniature sound decoder that fits your little critter just perfectly.
For the most part I use the 9 Pin JST connector. That gives me spare wires if I want to go back and put ditchlights on my diesels later. In some cases I also use drop in replacements for the existing lighting board (P2k 0-8-0, Atlas GP7).
rrebellTheir is a problem when standards no longer are standards. Now it seems everyone is going in different directions, kinda like it was in the beginning of DCC.
And that problem is the consumer doesn't hold the manufacturers to the standards. Also the standards may need to be revised or updated.
Actually I pretty much just hardwire everything, generally with a decoder that has a 9 pin, like a TCS T1. If the loco has an Athearn/Atlas style board, i may use a board replacement type, at least for sound, ie Loksound Select Direct. I have no desire to go through my locos that have motor only decoders and swap all the connectors for something that might make it slightly easier later on - I'm not going to install speakers without sound decoders, so switching connections really wouldn;t save much time. Considering mechnaical fitment is usually the biggest time consumer, a slight difference in the number if wires to solder is pretty meaningless. Even some of that is mitigated by having a fleet of similar locos - I have about 8 Atlas/Kato RS3's, and they are all getting Loksound sound decoders, so once I do one, the rest I can effectively mass produce since they will all use the same speakers, enclosures, and decoders. Even hardwired ones, like TCS T1 in Proto Geeps, including swapping the bulbs for LEDs. I've done a bunch of them, it doesn;t take me long now to do one as I have it all down, including at what point to clip the wires so they reach the connection points without leaving too much wire that jams against the mechanism or cutting too short requiring an extra piece spliced in. Initially it seems like a great idea putting in some sort of standard motherboard in every loco, but once you do a few DCC installs, especially if you have several similar locos, it's really no big deal just doing each one as you get to it.
rrebell Their is a problem when standards no longer are standards. Now it seems everyone is going in different directions, kinda like it was in the beginning of DCC.
Not really. The NMRA is just rather slow when it comes to technical change. The European manufacturers have updated the 21 pin design as the DCC world has evolved and the NMRA standard for it was never updated alongside it. Even TCS is inconsistent - Steam WOW 21 pin and Diesel WOW 21 pin aren't the same! One follows the old NMRA standard with line level functions and one follows the Euro standard with logic level on the extra functions. It should be relatively easy to rework a board that was built for line level outputs and change them to logic level, generally eliminating and bypassing a component or two, but going the other way is more difficult as you need to add the driver circuit somehow.
So if I just don't buy TCS decoders, do I avoid the issue?
The article from Streamlined Backshop I linked has a chart showing what works with what, and also notes from variou smanufacturers such as TCS, Bachmann, and ESU.
You also won;t be able to use the Soundtraxx Econami 21 pin decoders with a NEM motherboard, their outputs are also high level. Or you can use a TCS 21 pin motherboard and not use any Loksound decoders - outside of the little issue where TCS Wow Diesels are one way and WOW Steam are the other.
I wouldn;t preinstall anything in any locos. Just install the decoder as you go. The whole motherboard idea seems to be a waste of time, at least on any loco that conveniently already brings all the wires to one place, like most modern steam locos. All the pickups, the motor wires, and the light wires are right there in the tender. If you don;t want to deal with the factory board, which likely has some sort of connector already on it, just solder the wires from a decoder with a 9 pin connector and be done.