This is to clarify the large scale configurations. To begin with the decoders are all very similar.
There are the Aristo, Bachmann and USA Trains versions that have the conventional Samtec pins. The Magnum is the same except the pins are cut off. All versions have the 36 screw terminals. The main Samtec connector J1 will always have 12 pins. The second Samtec connector, J2, at the opposite end of PCB, will be manufactured with 11 pins but modified to 10 pins as needed.
This version will be modified to have J2 at 10 pins by removing pin 11. Note that there is no active connection for Aristo on any of the J2 pins. All the connections including the speakers, are active on J2A, the associated 12 pin screw terminal. To maintain mechanical connections on J2 the following pins remain intact: J2-2, 4, 5, 6, 7. In order to eliminate the possibility of shorts J2-1, 3, 8, 9, 10 are cut off flush to bottom of the lower circuit board.
This version will retain J2 at 11 Pins, all 11 pins remain intact.
Note: There are 6 active function connections on J2:
- J2-1 = Speaker # 1 (+)
- J2-2 = Chuff Trigger #2
- J2-3 = Speaker #1 (-)
- J2-8 = Class Lights
- J2-9 = Cab Light
- J2-10 = Fire Box
There are four new unique P/Ns for the popular PnP configurations:
- 3107-0v7-0-104.q2 K27 and 2-8-0
- 3107-1v7-0-104.q2 Climax
- 3107-2v7-0-104.q2 Forney
- 4103-0v7-0-104.q2 2-6-6-2 Tank
For stereo, the second speaker is connected to J2A, 4 and 5.
All the other Bachman locomotives do not have the DCC Socket and would use the Magnums.