So, I bought a DCC Ready HO scale Athearn RTR SD40-2 for once, and do my own DCC Sound installation as well as replacing the bulbs with LEDs. I'm fitting an ESU LokSound Select Direct, onto which I have downloaded and installed the SD40-2 sound file. I have only detached the pickup and motor wires and unclipped the motherboard from the chassis; the motherboard is still attached to the shell by the lighting wires. I stupidly assumed that the factory motherboard would have all the pads labelled up, just like the ESU is. Now it's off, I can now see that factory board has no + and - markings on the motor tabs. And to make matters worse, it only has one motor lead and now I have a guessing game on my hands - do I connect this wire to the MOT+ or the MOT- on the LokSound? My gut instinct is to connect it to the MOT+ Am I wrong? FYI the Athearn motherboard is marked 'G1551A'
And I would've been wrong if I'd done that... Just found the answer on the TCS site of all places. They've got photos for installing a WOWSound in this loco, and they replaced the Athearn board with their own RTR-MB1, which only has one motor tab. On the product page for the RTR-MB1 they kindly published a specs diagram which shows the Motor tab is 'Negative'