Micro Trains SW1500 DCC conversion

[bobdobbs]

Well just got my MT SW1500 yesterday, OK model, handrails not painted white, rear headlight package is a dummy, not lit and does not have clear lenses, just grey plastic.  Runs really well on DC, like a Life Like SW(X).  Flexcoil trucks look good, open gearboxes on trucks just like Life LIke.  Noticed when I put it on track, the front coupler height was a bit too high (?)  Yes this is a MT product so I assume the coupler height would be dead on.  The front coupler was too tight, the coupler would not center without a flick of the finger....

Anyway tried to instal a Digitrax DN126M2 decoder.  Tested decoder prior to install, readback "3" took a new Address (2510) took a factory reset back to a road number of 3.

Now be advised I have hardwired Digitrax decoders in 3 LL SW(X) switchers before and I would say for me it was a difficulty level of about 7 on a 1-10 scale, but all 3 went very well and still run great to this day..

MT and Digitrax provide shell removal and Decoder install instructions, and it seemd like an easy install.

Shell off, pull wires off DC board, pull DC board Put DCC board in put 2 wires in DCC board, shell on, test, enjoy.
Wrong.  When the insert DCC board step hit, the Digitrax board has thick solder on the top contact pads.  (which would be nice in other of their DCC Boards), but in this application combined with the crude Chassis casting made shoving the board in a difficult matter.  Now mind you I am following the directions but I had to apply alot of pressure to get that board in.  Anyway attach 2 wires put shell on put on Programming track, no Address 3 read... no response from decoder.  OK.  Remember that this model will not operate without the shell being on since the contacts from the trucks to the frame live on the shell...

Take shell off fiddle with board, put shell on try to program roadnumber 2510 in.  Nothing.  More fiddling with wires to board, board placement, check for shorts with continuity meter, etc.  Hook up leads to chassis without shell to programming track, decoder works fine, program roadnumber, reads back etc.  Put shell on, will not work.  45 min of fiddling with shell, decoder wires contacts, etc.  Finally get unit to run on regular track with shell on- cool.   Problem- one truck not making contact with worm gear, so unit is not turning all 8 wheels.  More fiddling, motor had became slightly dislodged during fiddling.  I notice that when motor properly seated, flywheel for rear truck is about .25mm from rubbing on one frame side more than double on other side.  Anyway put on track will not run with shell on, more fiddling 1 1/2 hours so far.  Get an Address readout on programming track, with shell, cool.  Put on main track BZZZZZZZ sound of a DCC short.  Pull off track in less than 1/4 of a second, too late WAH WAH game over.  Sending decoder back to Digitrax.  Unit works fine with DC Board.  If new decoder doesn't work, will have a DC SP SW1500 for sale in a few weeks I will keep you advised.  Hey Manufacturers hows about just using freaking NEM decoders in everything, My Fox Valley ES4400 DCC conversion took about 45 seconds.  Jeeez  plus remember the MT SW1500 is $135.00 MSRP and you are just getting the Life Like POS chassis (POS in terms of DCC conversion) DC it is fine.  I dont think the Digitrax decoder is at fault, I assume something on the shell is contacting the decoder and causing some problem
I cant figure it out.  One disclaimer, I have hard wired Decoders in at least 85 n scale locomotives including The atlas shay RS3's kato mikado, n scale brass etc, I am not an expert, but I am DCC battle hardened.

[Philip H]

There's another thread somewhere about that documents Dcc install in earlier 1500's. upshot of those is you have to put Kapton tape between the decoder and frame under the entire decoder or it shots to the frame.

[bobdobbs]

Well like I said in the OP, I have hard wired three of the LL non DCC locos successfully, I am discussing the new Micro-Trains Release which claims to be DCC Friendly.  There are provisions on the new model to avoid shorting between the DCC board and the frame, namely a thick piece of foam that the decoder rests on, I assume it worked in my DCC failure, not sure.....

[Ed Kapuscinski]

I talked to MTL about it. One of the problems might be the weight in the cab too.

Either way, I agree, it's kinda bs the way these eat decoders. If I were digitrax, I'd be mad.

[sp org div]

I am happy with the TCS Z2 we put in an old Life Like SW1200.  So had no hesitation in ordering the TCS specific drop-in board for my SP MT SW1500.  MB Klein still had a few in stock when I ordered mine the other day.  Their tutorial made it sound too easy. 
Ya MT missed the full gist on the light packages, but glad they followed thru as far as they did....  The light housings dont include enough thickness as the gyrating housings need for the motor drives, so all the lights are even across the width of the cab and nose.  Shouldnt be too bad to retro.  Oh well, mine is just a yard goat so it will only get fibers in the twin seal beams and call it good.
Good luck bob
Jeff
http://espeeoregondivision.blogspot.com/

[tehachapifan]

On my earlier release SW1500, I found a short between a solder joint for the motor lead and the frame, where a tiny hole had worn thru the electrical tape looking stuff. Unfortunately, this wasn't until after I fried my first decoder too after going through exactly what you had happen. Some Kapton tape over the hole seemed to do the trick on the 2nd decoder install (gotta love that Digitrax warranty! )

[peteski]

This problem and solution is documented in the 3rd post down in https://www.therailwire.net/forum/index.php?topic=35263.15 (by tehachapifan).  That was in February. According to the 6th post down MT was aware of the problem back then.  The problem still exists in the latest run?   

[rrjim1]

Bob,   I even tested my loco to see if the motor was isolated before putting in the Digitrax decoder. Everything looked great, but what ever happened it shorted out the decoder. Waiting for my replacement from Digitrax.
I have had shorts before and even a motor frame that was contacting the loco chassis. Not once did it damage the decoder. I just corrected the problem and everything worked great.
IMO a component on the bottom of the DCC board was touching the loco chassis. When I get my decoder back I will do a lot of checking and some modifying before installing the DCC decoder.       

[bobdobbs]

I will dissect my SW1500 and check for motor to frame shorts, but I agree with you the frame and or decoder are touching each other in bad ways, the clearance of the frame and components on the topside of the decoder and the frame pick up pads are very tight clearances.

[rrjim1]

The replacement DCC decoders that I received back from Digitrax were a lot narrower were they plug into the chassis. Much better fit, but I still had to file .007 - .008 ths off the solder that was placed on the top side of the board. Light board was .022, Digitrax board was .030 with the solder.  Both locos now look and run great.   

[bobdobbs]

Thanks, I will do the same if the solder is thick.  I did just dissect my Loco and no shorts from motor to frame, but boy the electrical tape and little clear plastic insulator at the end of the rear frame halves is very crude.  Like I said for $135 MSRP, I was expecting a bit more sophistication.  How much will the new Kato Amtrak engine MSRP for?  Whatever it is you really will get a modern well designed locomotive.

[rrjim1]

 The MT body detail and paint is way better than anything I have seen from any other of the manufactures. They runs just as good and better than some. This is what is important to me as I run trains more than anything else!

[peteski]

The MT body detail and paint is way better than anything I have seen from any other of the manufactures. They runs just as good and better than some. This is what is important to me as I run trains more than anything else!

It will run as well as Life-Like SW1200 (since that is what's inside the well-detailed body). It is no Kato by any means.  I agree though that Kato models suck big time!  Any mention of Kato's superiority in N scale makes me nauseous.

[rrjim1]

It will run as well as Life-Like SW1200 (since that is what's inside the well-detailed body). It is no Kato by any means.  I agree though that Kato models suck big time!  Any mention of Kato's superiority in N scale makes me nauseous.

The Following User Says Thank You to peteski For This Useful Post:

[bobdobbs]

Yea nice, anyhow awaiting my repaired/replacement decoder from Digitrax and will update on DCC progress.  I run the Sh*t out of all my engines, but Cant if they don't convert to DCC as advertised.  If I had it to do over, I would have just hard wired a DZ125 into the cab like all of previous LL SW1200/9's.  And I would be running this thing too.  The thing that I did notice on this engine was how thin and durable the handrails are, very nice.