The plugin was where I suspected and I plugged the dcc decoder in but now my problem is that the shell won’t go back on because the decoder is a tad long and strikes the plastic light thing inside the shell and the front light isn’t working. If I reversed the decoder in the socket it might would work but then the loco is in reverse when the controller is in forward.
Oh well, back to the drawing board.
end of edit
I have a new Atlas GP-7 that I’m going to try, for the first time, installing a dcc converter. This is the locomotive…
Mine didn’t come with very much instructions and the guy I bought it from also sold me the 8 pin Digitrax dcc converter for it. It is N scale but he assured me it would work.
Now I have no idea exactly where I plug the converter into so here’s a picture of the dc circuit board…
and a side view…
It looks like there is a clear plastic dummy plug beneath the area where the front light wires are taped together with black tape (on the right side in the first photo). My guess is that you snip the tape, move the wires out of the way, pull the plug out and plug in the decoder. But that’s all conjecture on my part.
If you could give me some guidance on where and how to plug it in, I would appreciate it.
You need either a decoder witha short wire harness, or one that repalces the Atlas board completely. I’m not sure what value resistors are already attached to those LEDs, if it’s near 1K you could just attach the same LEDs to the board replacement decoder. SUitable board repalcement decoders are Digitrax DH163A0, TCS A4X, or NCE DA-SR. These completely replace the entire circuit board int he Atlas loco and clip on to the same plastic tabs that hold the existing board. The connections are in exactly the same place - motor wires on the side, truck connections front and rear ont he outside, lights connect tot he middle two terminals on each end.
You have a post 2003 version, the earlier versions do not have 8 pin sockets.
If it will fit, I would still use a replacement board decoder as Randy says, even though Digitrax is suggesting a plug in decoder. It is a very tight fit inside an Atlas GP7, and the replacement board decoders leave a bit more room for airflow. As Randy says, they are easy to install.
Yes, even though there is a socket - as you’ve seen, there’s not much room for those decoders with the built-in plug (the -IP ones in Digitrax’s naming convention) which is why I say use the Atlas board replacement instead.
Side note, if you have an old Atlas witht he Kato drive, don’t spend the extra for the Kato version of the decoder - the K0 or K1 in Digitrax terms. The ONLY difference between the DH163A0 and the DH163K0 is they solder some wires to the truck leads so you can clide on the Kato connectors. And they charge $5 more for that. My solution was to open the connector a bit, it then slides right ont he circuit board for the A0 decoder, and then solder it on. I like a positive connection.
Thanks Nigel, I was a little perplexed at which model I had. Now I know. I like the replacement board also. I’ve been in the shell looking around and I was wondering where I would put the other type.
Randy, Nigel says I have the post 2003 model but I’m still going to try and find a complete replacement board. There is so little room on top of the board that’s currently in it I think it would be hard for a novice like to me to get an IP type to fit.
I got the two GTW units and put DZ123PS’s in them. It’s a simple plug-in install with no clearance or other problems whatsoever. When the D&TS units arrive I will do the same with them.
Undo the tape over the dummy plug in the factory board (you can re-use the tape if you’re careful) and replace the dummy with the PS. Re-do the tape and you’re done.
Thanks for the information, Steve. I cut the tape (doh!) so I’ll have to redo that. I’m going to a ‘larger’ hobby shop tomorrow so I’ll look up the decoders you and Randy have suggested.
Back to the original post, generally if you plug in a decoder and the engine runs headlight doesn’t work, it means the decoder is installed backwards. The engine would run backwards…but of course that depends which end is the front, it can be harder to tell with a diesel. I think Atlas GP-7’s are all set to be short-end first even though many prototype railroads considered the long end the front.
<> Anyway, since you said if you rotate the decoder 180 degrees it fits, do the headlights then work?? If so, I wonder if that could be the problem?? Otherwise you could to get a 9-pin decoder with a short (1/4") harness (for connecting the 9-pin decoder to an 8-pin plug-in). http://www.loystoys.com/indexes/decoder-harnesses.html
Or just use a board replacement as suggested earlier, they work well and are easy to do. [:)]
Don’t discount the -PS (1-inch wiring harness) or even the -P (5-inch harness) decoders. They give you the simplicity of plug-in installation, a lot of flexibility as far as decoder placement, and are usually less expensive than the board-replacement decoders.
I’m not knocking the board-replacement decoders. I’ve used plenty of them myself and will continue to do so when I think they’re right for the application. For example, if you want the additional functions for beacons or ditch lights or whatever, they’re the only way to go.
But in this particular instance (late Atlas GP7 w/motor control and factory lights), the DZ123PS is easier to install, fits just fine, and has an MSRP that’s 33% lower than the DH163A0.
The lower price isn’t because it’s a generic decoder vs a board replacement. The 163 decoders have 6 functions vs 2, and Back-EMF motor control. The Digitrax web site says the DZ123PS has Back-EMF but then also says it has Economy Series 3 features, which does NOT include Back-EMF. Might not be needed on a qualkity drive like Atlas, but in that case the NCE DA-SR is only $2 more than the DZ123PS.
