alright, so ive been doing some research, trying to figure out which decoders I should get to install in my engines. What is the difference between 7 pin and 9 pin? And then theres the NMRA 8 pin plug? Gah this is so confusing.
Heres what I have:
Athearn GP35, Athearn GP40, Athearn GP9, Athearn SD45, Athearn SD40T-2, and some Atlas and Atlas/Kato RS-1's.
If you guys could all be so kind as to point me to which decoders would be best for these engines, that would be awesome. And, all of these are sort of old, before anything coming DCC-ready, except for possibly the RS-1's. I'll have to check those out and see.
I just want motor control, with some lighting functions. Thats it.
I've been looking at NCE decoders, and it looks as if i'll be going with them exclusively, except for TCS decoders, which look pretty good (and I like their site).
So... thanks so, so much in advance for everyone who replies.
the difference between 7pin 9pin 8pin...ect is how many pins there are in the plug which varries on the number of wires running too the decoder.
You said your engines are old, how old? If those athearn are the old Blue Box athearns then you need something like this too make it DCC ready. http://www.digitrax.com/prd_mobdec_dh123at.php
Greg,
I have never seen a 7 pin plug, and there is a standard for a 6 pin plug(but I have never seen one). The NMRA proposed a 6 pin and 8 pin plug back in the 90's. Several years later the JST 9 pin plug format became very popular in the electronics industry.
Some newer engines have capability for both the 8 pin and the JST(9 pin) plug layout. The JST is a very compact 'in-line' layout and has become very popular with DCC manufacturers as they make the decoders smaller.
I know many of the Digitrax decoders now use the JST format on the actual decoder. You can order them with a 'wired' cable, or with a 8 pin plug/cable if needed. I added DCC decoders to a pair of Atherarn SD40-2 engines and they had a cable that plugged into a 8 pin socket and had a JST connector on the other end. I pulled the 'wired' cable off of my Digitrax decoder and just plugged the two together - 10 minute decoder install!
In the case of the Atlas RS1's - they did not have a decoder socket. I used a DH163A0 decoder that replaces the original Atlas 'light board'.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
The majority of my units have 8 pin quick plugs. For those, I use TCS T1 decoders with 8 pin harnesses. My Atlas RS3s have TCS AX4s. For the oddball units I use TCS's application chart or drop them an email.
With the exception of the A and D series decoders, TCS decoders have a 9 pin JST socket. When you order the decoder, you can order a harness with a JST plug on one end and an 8 pin plug on the other. The harnesses are available in several lengths for different units.
Nick
Take a Ride on the Reading with the: Reading Company Technical & Historical Society http://www.readingrailroad.org/
yeah thats what i'm saying.... ALL of my engines are NOT DCC-ready (unless the newer Atlas RS-1's are, which I have yet to check out).
ive been looking at the Digitrax and Litchfield Station websites... would "light board" replacements control the motor as well as the lights? I'm just having so much trouble grasping the... procedure, I guess, for installing decoders and understanding what I need, and which loco needs what, etc.
but yeah, everything i have is NOT Dcc-Ready, which means it would all be hardwired, however the hell I would do that.
Yes -the Atlas type decoders control the motor and the lights. They aren;t all simple drop in, however if you look at the existign light board on the loco, if the Atlas style decoders will work, it will have a board with 2 pins on each end to conect to track power, a pair of pins in the center of each end conencted tot he lights, and one side will have the connections to the motor. The Atlas style decoders look exactly like this - bascially everythign connects to where it did int he same physical place on the original board. Atlas maintained much the same design as Kato, from the earlier tuimes when Kato built the locomotives for them. The primary difference in the Kato is that the motor leads come off opposite sides near the middle of the board, and use tabs of copper for the motor leads rather than wires. You can use the Atlas style decoder in these, just shorten the tabs so they don;t short out on anythign and solder short pieces of wire to them. There are decoders that just trap the tabs much like the stock spring wires do on the Kato boards - I don;t trust these, i solder everything. Same with the track pickup wires - they are typically just pushed through a hole in the board and plastic cap goes on the end to hold it in place. The decoder boards usually don;t fit those little caps very well - again I just solder the wire on. older kato/Atlas locos didn;t have frotn and rear lights - they had just one bulb in the middle. You'll need to cut down the light bars and add a second bulb to have lights at both ends when using a decoder, or (I'm not trying to confuse you futher, but in most cases this IS a better choice) use LEDs with resistors instead of light bulbs. Bulbs can get hot and melt the plastic. Also they burn out and need to be replaced.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
okay... i'm still pouring over the digitrax site and litchfield, and i'm still stumped as to why the NMRA standard is 8-pin, but this JST thing is 9 pin....
let me get this straight, though. The decoder plugs into the NMRA socket thing. The NMRA socket thing is what is wired to the engines circuit board/engine. Yes?
edit: Wait wait... okay, I think I get it now: The JST harness thing is an ALTERNATIVE to the NMRA socket, yes? Looking at the NCE decoders makes it a lot simpler, the way they are labeled at litchfield. Everything else is so confusing....
So, I have the option of hardwiring an NMRA socket OR a JST harness thing to the engines circuit board, to which to connect a decoder to?
DeadheadGreg wrote:So, I have the option of hardwiring an NMRA socket OR a JST harness thing to the engines circuit board, to which to connect a decoder to?
Since you seem to be favoiring the NCE, My advice would be to consider the DA-SR for the entire lot other than perhaps the RS1. I don't know if the hood is wide enough or not. For all the others this decoder can be placed on top of the motor with double-sided foam tape. Personally I find the flat format easy to understand. Power on the outside edges, motor control in the center, lamps in the center of the long edges. As I recall it even says right on the circuit board which side goes toward the front of the loco.
If you want a smaller format the D13SR works well in almost everything. Cut off the extra wires you don't need to prevent them binding things up. I've never used one but NCE makes a KRS-SR that looks like it was made especially for the RS1 type application.
You might still be a little confused, but I'm not totally sure.
Some locomotives already come with an 8-pin socket that is part of the light board. There is a dummy jumper plug that plugs into this socket which allows the engine to run on DC. When you buy a decoder that comes with the 8-pin thing, it comes with a plug, not a socket. What you have to do is remove the dummy jumper plug on the light board and plug in the 8-pin decoder plug. Then you're done. Typical of this light board design would be some of the Atlas Silver Series diesels and the Trainman series diesels.
The newer Athearn Ready to Roll series engines come with a light board that has an 8-pin socket as well as a JST connector on the end of a short harness. In this case I believe that the JST connector has the dummy plug. For this engine you can install either a decoder with an 8-pin plug, or a decoder with a JST connector. In either case, you have to remove the dummy connector if you install a decoder.
You do not have to "hard-wire" the socket unless you are removing the light board, re-connecting all the wiring to a socket, and then plugging the 8-pin plug on the decoder into the new socket. If you wanted to do this, you would be better off just hard-wiring a decoder into the existing wiring in the first place.
I think this should answer your question, if that is what you are really asking.
Regards!
Actually, the 8 pin connector with 2 rows of 4 pins AND the JST 9 pin inline connector are BOTH in the NMRA RP. COmpanies liek TCS sell a variety of harnesses that plug into the decoder with the JST connector and on the other end have plain wires, an 8 pin plug in various configurations with varying lengths of wire, or other 'special' clips like the ones Digitrax sells for old Athearn locos. I like to solder things in place rather then rely on clips or contacts, with a decoder that DIDN'T have the JST connector I'd be kind of hosed if the decoder fried, sicne it would essentially be soldered into the loco. With the JST plug, I can simply unplug the decoder and pop a new one on, or upgrade to one with more features if I needed to. Also, you cna make a 'dummy plug' for the JST connector (newer Athearn locos come with these - pop it off, and pop on a decoder with the JST connector and you have a DCC loco) and switch the loco to pure DC.
The various JST to 8 pin harnesses that TCS sells are designed to make it easier to fit the decoder in various brands of locos without having to cut wires or try to stuff long lengths of wire inside the shell somewhere. Different locos with 8 pin socket put them in different palces inside the loco, and oriented in different ways. So the harness meant for one brand will work in another, but it may end up with the decoder pointing out past the end of the loco unless you can fold it over, whereas the correct harness would place the decoder right where a naturally occurring open space is in the frame where it can sit and not interfere with putting the shell back on.
This is one of my hard-wiring jobs in an Athearn SD40-2. Used a Digitrax DH123, 9-pin JST plug.
The decoder fits up in the cab area, because the back is filled with weight. No headlights on this one either. I left enough wire to add some if I feel like it. I used one of the Digitrax Athearn harnesses once. Too much wire to tuck away when done, and I had to resolder some of it anyways.
The only tricky part is soldering wires to the motor. Remove the bronze clips, make sure the brush springs don't fly away, and solder while they are off the motor. The rest is figuring how long the make the wires, and putting them in the right place.
Finished, except for the TCS decoder I plugged in later. I can also take the decoder out and plug in a dummy plug, which allows for DC use. Athearn RTR and Genesis with Quick-Plugs come with these plugs, to allow DC operation out of the box. When I install something with a JST plug, I use the dummy plug and test the wiring on DC, before plugging the decoder in.
This part is vital: Insulate the frame from the motor!
Mike WSOR engineer | HO scale since 1988 | Visit our club www.WCGandyDancers.com
Little trick for old Athearns - since you have to take the clips off to solder the wires anyway (well, you don't HAVE to, but melt the palstic end of the motor just a little and you can toss it..), reverse them - the one from the bottom has an extra tab that goes out to contact the frame, so use that one for the top instead. Other than that tab, they are identical. You still have to insulate the motor cavity - Kapton tape is great for that - it's thinner than electrical tape AND stronger - but keeping that pesky tab out of there will prevent it from eventually wearing through the tape and causing a short at some random time in the future.
wait, what clips?
arrrgh... this is all so annoyingly confusing. I can't wait until tomorrow when I ahve some time to sit down and open up some engines to check out how all this **** applies to reality...
Look at his third picture, you cna sort of see them, little brass or bronze strips on the top and bottom of the motor. The gray wire is attached to the bottom on. On the Athearn motor they serve to hold the motor brushes in as well as provied the contact points for pwoer to get to the motor. Old Athearns like that don;t have fancy circuit boards and wires connecting the track pickups to it and the motor, it was all done with various clips.
Look at this photo.
I have an Athearn BB motor turned up on it's side so the bottom can be seen. See the copper strip? The strip on top is identical save for the two prongs you see sticking off. These strips can be switched, top to bottom and vise versa. But be careful when you remove them as the brush springs like to go flying. I just leave the strips where they are and simply break the two little prongs off. I then solder a thin wire (same gauge as the decoders wire) to the strip.
Athearn "Blue Box" engines were designed many years ago to be simple to build on the assembly line. Rather than having connections that are soldered together, they're designed to have pieces of copper strip that snap in place and rub against each other as the trucks turn to connect the trucks to the motor. It works, but most of us replace the copper strips with soldered in wire connections which prove to be more reliable over time.
Lionel Strang's DCC Made Easy book from Kalmbach has a chapter on doing an Athearn decoder install that you'll find very helpful...actually, it probably would explain many of the questions you have now about DCC.
great, thanks, i did not know about that book.
I'm going to be sending a few engines out to Gerry at Maine Trains to do decoder installs, as well as get my NCE Powercab for the steal price of $143.95. He charges only $25/hour labor, which I think is quite cheap.