Greetings all - Recently I undertook my first brass locomotive DCC install: An Alco Models FM H20-44 switcher (ca. 1977): Actually it surprisingly turned out to be an easier project than I anticipated because the motor brushes were all nicely isolated from the frame; not what I was expecting from an older brass locomotive. I initially installed a TCS M1P decoder into it to see how well it would run. It actually ran well, although it required an occasional push or two when running on speed steps 005 or <. After 45 min. of break-in at various speeds in both directions, she'll now do ~0.25sMPH - with no hesitation. I'm looking at installing sound in it now and speaker placement has been the most challenging to figure out. I think I finally have a place for a "sugar cube" speaker(s) and have two of those on order, along with a Loksound Select Micro decoder. While I wait for the package to arrive from TTE, I decided to tackle my other DCC installation project: A brass NYC M-1 0-10-0 switcher: Even though I've been working on the H20-44, this is new territory for me. So, I looking for any expertise and wisdom you all are willing to impart in my direction. I just want to make sure that I don't miss anything important. I removed the shell from the frame, which came off easily after removing one large screw on the underside of the boiler and two tiny screws at the back of the cab: I used my trusty multimeter to probe all around the frame. As is common on these older brass steamers: Power is picked up from the engineer-side drivers then travels through the gear box, drive shaft, motor wiring, draw bar/draw bar pin, before exiting out the trucks on the fireman-side of the tender. Here is the view of the motor and draw bar: If I disconnect the motor wire from the 2 'o clock position terminal, this isolates the motor from the brass plate on the front side of the motor, where it receives power from the drivers via the gear box and drive shaft. If I disconnect the motor wire from the 8 'o clock position terminal, this isolates the motor from the draw bar. No surprise, in either case. At this point, is the motor completely isolated from the rest of the frame? Or, is there anything else I need to test or check before proceeding on? In the event that I install a decoder in the tender, my plan is to replace the uniform-color motor wires with orange and gray wire. (Or, perhaps black so that it will be less conspicuous between the cab and tender.) Is there any way to determine which brush terminal is positive (+) and which one is negative (-)? For track power: Can I use the brass plate on the front of the motor housing for the right rail and the draw bar pin on the underside of the tender for the left rail? Lastly, am I forgetting anything important? Thanks for the input ahead of time.
One issue resolved: A fella on another forum recommended that I connect a 9V battery to the motor brush terminals to determine which one was positive and negative. The idea worked so well that all I had to do was span the gap between the battery and motor terminals because they lined up perfectly. So, the right terminal in the above picture is positive (+) and the left one is negative (-). That was too easy...but I'll take it.
