The 7100 series don't have plugs, they are a simple board replacement, like the Kato built units befor them.
It depens on the year released, but you cna go by road name/number to see when they were made:
http://archive.atlasrr.com/HOLoco/arc-hors1.htm
The 2008/2007 ones I think have 8 pin sockets, but still, it's a simple board replacement. The same board form factor works for all Atlas and Atlas/Kato locos as they all have the same tabs on the motor mounts the support the board, be it the original Kato plastic 'board', the simple circuit board with 2 diodes for directional lighting on the early 7100 series, or the board with the 8 pin plug like later 7100 series, if they ever got plugs. So just get a decoder meant for an Atlas board replacement and you are good, don;t worry about the plug.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I've got a question regarding dcc capabilities in earlier production Atlas RS1 HO diesels. I suppose the topic pertains engines other than the RS1 series as well.
Atlas' current lineup has the "gold" series (dcc and sound pre-installed) and "silver" (which I believe has a connector for a decoder). These products carry the Atlas product numbers "10 xxx xxx".
My questions pertain to the earlier production runs with the product numbers in the "71xx" range:
Are they all strictly DC, with no plug for a decoder?Or do some have a dcc connector, as well?
If so, is there any way to ascertain which ones without actually opening them and examining?