Suggestions for Micro-Trains FT decoder install

[R L Smith]

I have a Micro-Trains FT set that's been on the shelf for years. I ran them on my DC Christmas Tree loop, and both units ran great right out of the box. I decided to install decoders and get them on the layout. I purchased a pair of Digitrax DN163M0 decoders, knowing full well they were probably on the hobby shop shelf for almost as long as the FT's were.  Anyway, I need some assistance...

I started with the B unit and installed the decoder per the instructions.  On the programming track, the headlight would flash once and give me an error message. I re-checked everything with a DVM to verify the motor tabs were isolated from the frame, and the decoder pads were contacting the frame slots. Still no joy.

I turned to here, and found a thread from 2016 that included a tutorial on hard-wiring a decoder onto the MT light board. I had some small Lenz decoders on hand, so I tried it and it worked like a charm! The B unit is alive and well. (Note, no headlight - just four solder connections after making the cuts on the original light board.)

Turning to the A unit, I installed another Lenz decoder onto the original light board (six solder connections this time). Nothing - just error messages on the programming track. I removed the board and installed the other new-old-stock Digitrax decoder, with the same result as the first one - the headlight flashes once and then an error message.

So I am batting 0.250.  Before I risk another decoder, any thoughts on that the problem might be? I have verified the motor tabs are isolated from the frame, and the pads on the circuit board are making contact with the frame. Photo of the B-unit install below.

Thanks in advance...

Ron

[peteski]

Ron,
I have never done a DN163M0 install, but flashing headlight seems to be a good sign.  How many times did you try programming it?  Did you try multiple times and did the headlight flash every time (then error out)?  If that is the case, the decoder is probably ok, but there is not enough of a load connected to the decoder for it to produce the programming acknowledgement current pulse to the command station (in programming track mode).  So it errors out. This usually occurs if the motor is not properly connected to the decoder.

Do you know for sure that the motor contacts had positive connections to the DN163M0?

Another basic test would be to try running the loco with that DN163M0 decoder using DC power.  Digitrax decoders by default have DC mode enabled.  So just take a 9V battery and touch its terminals to the loco's wheels and see it the motor starts running. If not, there is a good chance the motor leads do not connect to the decoder.

[thomasjmdavis]

I did a couple MTL FTs a few years ago, using the DN-163 MO, and had one issue that I can recall (see below). I used the guide from Digitrax, available online if you don't already have one:
https://www.digitrax.com/media/apps/products/mobile-decoders/dn163m0/documents/DN163M0.pdf  Everything worked fine in the end.

The problem I had was in the second half of Step 5 on pages 2-3-

©2010 Digitrax, Inc. www.digitrax.com 3
Press down and slide the board back and under the frame clips
to lock the board in place. Be careful to keep the motor clips
between the bracket and the motor brush caps on both sides
of the locomotive and not bend them.

I did not bend the motor clips, but the one issue I do remember was it being harder than I expected to get the motor clips correctly positioned while getting the board back under the frame clips.  I may also have tinned the contacts on the board with a very thin layer of solder to get better contact with the frame clips.

[R L Smith]

Thanks both of you. I did pre-tin the pads on the circuit board, and agree that getting the tabs to line up over the motor contacts required some extra attention.

I will try it on DC and report back later this week. 

RLS

[R L Smith]

Problem solved!  Peteski questioned whether the motor contacts were actually making contact, since the headlight would flash on the programming track.  I took the original board (to which I had soldered the Lenz decoder) and cleaned the contact tabs with a pencil eraser.  Turns out they were pretty oxidized. Re-installed the board and it programmed fine. Now I am happily running the Micro-Trains pair on the layout. Considering how long they sat in a box, they run really well.

Thanks all!


RLS

[peteski]

Thanks for the followup.  Good to know that the problem is fixed.