woodone Hard to belive that it took us 37 replys to swap two wires.
Hard to belive that it took us 37 replys to swap two wires.
Not really. About halfway through the frist page the original poster said he would swap the wires when he had time. Then the thread veared off into a discussion about how DCC color codes aren't always right and DCC Ready isn't always DCC Ready, and a little bit of Digitrax bashing to top it all off.
If all else fails, just follow instructions.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Alton Junction
Doggone it, David, you were right again.
Today I finally had the time and material to experiment a bit more on this loco. I ripped everything out down to the feeders, and reinstalled the decoder with the orange and gray leads swapped. That did the trick, I now have a "front" headlight that lights when the loco is moving forward, and goes out when direction is reversed. At least I got some more decoder installation practice. The installs seem to get neater the more you practice.
Thanks for all the suggestions.
Jim
Visit look4trains.com
Having been op DCC 19yrs and fitting decoders on a commercial bassis I think I know a little about decoders and the fitting/programing of them.
Early Digitrax decoders were often a problem in one way or another.
The newer ones may be different but once bitten twice shy as the saying goes
I have retired from fitting decoders on commercial basis but am often told of problems with Digitrax decoders by fellow modelers.
The only non sound decoders I use these days are DCCconcepts or TCS.
Cheers
Ian
Haven't tried the lates ones since I am more than happy with TCS for my non-sound locos, but the previous ones, 163 and 165 series, have HORRIBLE BEMF. Big jumps at a couple of speed steps no matter what you do, because they gather all the 'error' you get when doing calculations in binary (rounding errors). The latest ones supposedly improve the BEMF, but I've settled on TCS as my standard for motor only, and Loksound for sound, no other decoders will go in my locos.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
retsignalmtr There is nothing wrong with Digitrax decoders. It may be just some of people that are using them.
There is nothing wrong with Digitrax decoders. It may be just some of people that are using them.
I have to say, this is one interesting thread !
I know very little about Digitrax decoders and don't want to know.
Won't use them even if given to me.
Now, does said Digitrax decoder have CVs to set direction of lights?
If so, set CV29 bit 0 so loco goes forwrd when direction is set for forward etc.
Then alter direction of light via CV so it shines when going forqard.
I E, if loco is going forward but light is not coming on or showing in reverse then alter Cv so light shines when loco is going forward.
Now this may mean that light is set to shine in reverse when loco is going forward.
In other words, when loco is is going forward adjust light direction Cv so light shines at forward end when loco is going forward.
Or has been said, swap motor leads.
NMRA Standard S9, Item II A:
http://www.nmra.org/standards/sandrp/s-9.html
One of the oldest ones - obviously would be hard to run doubleheaded locos if one ran forward with the right rail positive and the other ran forward with the left rail positive. Since steam locos typically did not operate tender to tender with a boiler facing each way, the way you often see diesels.
You didn't think it was just dumb luck that most every loco runs the same way on DC so they can all run together, did you? Gotta say, there would pretty much be no hobby had those guys not gotten together back in the 30's and established all these standards. And then pretty much made manufacturers comply if they wanted to sell any product. The NMRA can;t force anyone to do anything, but since everything is standard, if you want to sell an HO train then it darn well better match the HO standards.
rrinker Only way to prove that out is to test on DC, and check your polarity on the rails. NMRA standard is the right side rail is positive for forward, so for north american locos, if the rail on the engineer's side is positive, the loco should move towards what should be the proper front. If it moves the opposite way you expect, then the motor wires need to be reversed, and orange will connect to grey, and grey to orange. It's also possible that the way the factory board is wired, it runs the correct direction on DC, but rip that out and put a decoder in (or bypass it, as many plug-in decoder installations do) and it might run the other way.
Only way to prove that out is to test on DC, and check your polarity on the rails. NMRA standard is the right side rail is positive for forward, so for north american locos, if the rail on the engineer's side is positive, the loco should move towards what should be the proper front. If it moves the opposite way you expect, then the motor wires need to be reversed, and orange will connect to grey, and grey to orange. It's also possible that the way the factory board is wired, it runs the correct direction on DC, but rip that out and put a decoder in (or bypass it, as many plug-in decoder installations do) and it might run the other way.
Well, I'll be. You learn something new every day. I did not know that.
I always rip out factory boards, because after attempting to analyze them and see what goes where, they are mostly a cluster you-know-what. Particularly those P2K ones witht he big resistors and the traces marked with an X to cut when switching to DCC. I drew out the schematic on one of those by following the traces. After cutting the required traces, only 1 of those big dropping resistors is actually in the circuit. Since I always replace light bulbs with LEDs - it's just easier to rip it all out and run wires to the proper location. It's not difficult, especially if there already are wires running to that factory board. Once removed, it's pretty obvious which wires come from the left side of the trucks, which come from the right side, and which go to the motor. The kicker can be the motor polarity. Understandable that it might be opposite what you want when invoilving a loco that ran either end forward depending on the practives of the prototype, good luck having a manufacturer change the wiring to that level of detail, considering the chassis might not even be made in the same factory as the shells. I'm amazed they got the decals correct, even if it does run the wrong way. But an end cab switcher - that's just silly to have it backwards. Only way to prove that out is to test on DC, and check your polarity on the rails. NMRA standard is the right side rail is positive for forward, so for north american locos, if the rail on the engineer's side is positive, the loco should move towards what should be the proper front. If it moves the opposite way you expect, then the motor wires need to be reversed, and orange will connect to grey, and grey to orange. It's also possible that the way the factory board is wired, it runs the correct direction on DC, but rip that out and put a decoder in (or bypass it, as many plug-in decoder installations do) and it might run the other way. Pretty sure this is the case with the Proto Alcos. I don't recall them running backwards on DC, fighting most every other loco.
htgguy It runs backwards when NDOT is set to forward. I will try swapping the motor leads after I have some more shrink tube on hand and let everyone know the results. Jim
It runs backwards when NDOT is set to forward. I will try swapping the motor leads after I have some more shrink tube on hand and let everyone know the results.
Flip the motor wire connections and see if that solves the problem with the lights.
I still say that the best....and easiest....test is to run a DCC ready loco on a DC powered track before installing the decoder. That way, you see if the loco runs at all, you see the directions of travel, and you see if the lights work.
Next, you test the decoder on the work bench before installing it to be sure that the decoder and its function outputs all work correctly.
Then, you install the decoder.
hon30critter I think that David B knows his way around decoders. I agree that getting the motor wires right in the first place will save you a lot of grief! Dave
I think that David B knows his way around decoders.
I agree that getting the motor wires right in the first place will save you a lot of grief!
Dave
Well, you'd THINK that matching the decoder wire color to that on the loco SHOULD be correct. Unfortunately, not always. Just more proof that "DCC Ready" is nothing but words with little meaning.
I think more first-generation Geeps and other road switchers were run long hood forward than were run short hood forward. Which makes it funny that LL set up the P2K versions to run short hood forward. Short hood first more started with second generation units, most railroads running them short hood forward, except for holdouts like N&W and Southern - they even ran locos as new as GP50's long hood front. One often notable exception was the FM Trainmaster - even railroads who ran their other road switchers long hood front ran the TMs short hood forward, because they were SO big it was harder to see around that giant long hood.
As usual, there are always exceptions. Always best to research your desired prototype for guidance.
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
Jim,
With CV29 set to normal (forward) direction, is the loco moving forward or in reverse?
The motor is connected orange-orange and grey-grey. I did do the modifications required to make the loco DCC ready, including milling out the frame below the lower motor brush.
I can get the direction of travel to change, but the headlight direction changes along with it. I will try the CV 33 and 34 combo someone suggested to see if that works. If not, might just pull everything and start from scratch again. It won't be for a few days, though, since I am waiting for more shrink tube and more time. Especially the latter.
Thanks for the suggestions all.
Heck, don't even pull the decoder. Lift the shell and see which way the motor is turning. Gonna have to do that anyhow if you need to flip the two motor wires.
If the motor direction and headlight direction are out of sync, changing NDOT (the normal direction of travel) will NOT fix that issue. It does just what it says, it changes the 'normal' direction of travel, when you tell the loco to travel in forward, it travels in what it considers reverse and turns on the reverse headlight. When you tell the loco to travel in reverse, it travels in what it considers forward and turns on the forward headlight. The purpose of NDOT is for situations such as a loco that is ran short hood forward on most railroads but long hod forward on some. NDOT lets you change which end of the loco is considered forward, but does not change the mapping of the headlights relative to the motor.
If the motor has been wired in reverse by LL, always a possibility, then the OP is not reporting correctly, because he says that he has already messed with direction on CV29 to no effect.
One way to be sure is to pull out the decoder and run the loco on a DC track. That will tell with certainty the direction of travel as the loco is currently wired.
It's not that the wires are connected the wrong way, I'm sure he connected orange to orang and grey to grey (P2K has color coded wires) - it's more that LL put the motor in upside-down. Mine are both goofy-wired too, orange to grey and grey to orange, because they run in reverse. Not sure how they goof that up, it's not like a road switcher that may have run one end forward on one railroad and the other end forward on a different railroad. I have to flip flop all my GP7's, too. They have them decaled properly witht he little F indications on the end of the frame, but on normal DC they run with that as the rear end, and also on DCC if the colors are all matched.
That Proto S-model issue also applies to the Atlas ones. They look nearly identical inside - probably made by the same factory anyway. Right down to the purple end cap on the motor.
I think David B has the answer, the wires to the motor are reversed. Because of that, the decoder is sending DC to the motor to make it go "forward", and also it turns on the forward headlight...but because the wires are reversed, the polarity is reversed, so the motor turns the wrong direction and the engine goes backwards. Fiddling with the CVs might eventually solve it - you'd have to set it so the headlight goes on when the engine is backing up, because when the decoder thinks the engine is backing up is when it's really going forward due to the wiring error. Othersise, you could hook the front headlight up to the wires for the rear headlight (and vice versa if using both). But, probably easier to fix the wiring error.
Regarding the orange wire that Randy referred to, the problem exists on the P2K S1, S2, and S3.
Here is the fix.
http://www.tonystrains.com/tonystips/2001/120601.htm