American Z Line First AZL RS-3 DCC Conversion

rray Jun 23, 2020

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  1. rray

    rray Staff Member

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    Rush job, I gots to be first don't I?

    The RS-3 has a decoder. My unit runs like a grinder at low speed, but it had some large dust inside, as though it was sitting on the production floor for several days collecting fallout and debris, before a shell was put on it. I can live with that, i'll order some TC tuner cleaner and spray it out later.

    So, the Digitrax DZ126T is exactly the same width as the PC board inside the loco:

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    I had to peel off the shrink tubing from the decoder, then replace the super thick LED wires with micro litz wires.
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    I cut the stock board off at the large resistors, and soldered the orange and gray motor wires to their solder pads, then flipped the board over and scraped the green coating off the traces for the power and soldered the red and black wires on the topside of the board. I also had to scrape away the trace that powers the rear LED because it contacts the frame.
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    After removing all the diodes and caps, I used one of the cap solder pads as the rear LED negative (Yellow wire replaced with black micro litz wire), and soldered the rear LED positive (Blue wire replaced with red micro litz) to one of the removed diode solder pads. That completed the rear LED wiring: 3.jpg
    This view you can just barely see the orange and gray motor wires from the decoder to the large resistor pads on the underside of the front of the AZL board. I had to have overlap of the boards to get everything to fit:
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    I pulled the slack of the micro litz wires and taped to the top of the board so theu would not get pinched in the side of the shell when I put it on. As for the forward LED, I could not use the cutoff board piece, so I just did chip on chip soldering of the original LED and 2.2K resistor directly to the micro litz wires and tucked it in front of the decoder:
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    The shell just slid right on without incident, and I tested the decoder and light operation OK. Not super bright, but no light leaks through the shell either with those 2.2K resistors on the LED's.
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    So, where there's a will, there's a way. You can convert this loco to DCC, you just have to have good soldering skills.
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    Here's my test video, just be aware that I still have to setup the CV's for this decoder to tune it's operation a bit smoother:
     
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  2. bostonjim

    bostonjim TrainBoard Member

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    The paint looks great on the NP. Curious that a loco would lay on the floor for any period of time...hmmm. I hear lots of road names are being offered. Does anyone know if New Haven is? Will you be updating some of the details with BLMA parts? It is great looking right out of the box. Looks like you couldn't wait to get home. Jim
     
  3. JoeS

    JoeS TrainBoard Member

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    So being as I’m a DC guy why does the decoder change the slow speed like that? I never understood that part of it.
     
  4. rray

    rray Staff Member

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    The decoder don't change the speed, it's that my sample has some grit in the gears and makes a grinding sound. When I took the shell off, I seen dirt and grit in the first one, and it only had 3 screws. Today when I opened one, it was a different loco than I opened up 3 days ago, and it too has grit and particles stuck all over it. I pulled out a fiber strand from the gear tower. I had not yet test ran them, because I took AZL's word for it that they tested them all. With the default decoder settings, I needed to reach speed step 7 before the loco ran smooth, less than that and it was jerky, and it makes a grinding sound like dirt stuck to the gears.

    If AZL just put it on a track and turned the power up till it started moving, then back down and the other direction, they would see that it works and ship it. I am talking very slow speed, like if I was going to couple and uncouple automatically, that's where the grinding speed is. I clearly have to make a video to better explain this effect. There is nothing wrong with my loco, other than some dirt inside it's mechanism. Nothing rubbing, nothing binding. Maybe possible a piece of plastic flash on a gear tooth, but once you ramp the speed up to say a scale 20 mph, it runs great. I simply programmed the starting speed to the level that the jerkiness was overcome, to verify it is running OK.

    As far as detailing, yes I am going to detail it. While lifting the shell, I discovered the bell bent over very easily. I think it's partially broken, but it is too small anyways, so I will replace it with a larger more NP prototypical bell. I also want to replace the couplers with MTL, but I can't find any here so I need to order some. The BLMA parts are long gone, it's a classic case of large company buys small company and drops the low profit details, so I doubt we will see the BLMA detail parts for sale again. I can raster a convincing fan and other details though.

    I am very pleased with this model, but like anything, I am picky and try to get a more prototypical appearance if I can. Prototypical as in NP Specific. :D

    This DCC mod was just about proving I can do it, and doing it before someone else does. It don't mean my way is the best, just the first. I hope someone finds an even easier method to install a decoder in theirs. Best would be a drop in replacement board, as there is plenty of real estate on that board for DCC instead of just DC components. The space that those 2 huge 1.3 ohm resistors is fully enough for a full 4 function decoder in SMT.
     
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  5. Kurt Moose

    Kurt Moose TrainBoard Member

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    Yup!;)
     
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  6. Chris333

    Chris333 TrainBoard Supporter

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    What are the 3 yellow stripes in the middle of the yellow for on the short hood?
     
  7. ztrack

    ztrack TrainBoard Supporter Advertiser

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    Rob great job! Yes we do test run all locos at mid speed. We run in both directions for a few minutes to see the behavior. This run was almost perfect with near 0 rejects. I can’t wait to see you detail these!
     
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  8. rray

    rray Staff Member

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    Those are safety reflector stripes, NP was among the first in the business to use them.
     
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  9. rray

    rray Staff Member

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    I did a second DCC conversion this morning, and the loco runs super smooth even at super slow speeds. I'm going to take the first apart after I convert the 3rd loco to figure out what's wrong.
     
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  10. rray

    rray Staff Member

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    And, I got the third one converted, now all 3 DCC. Getting too hot in the garage, time for a Berry Margarita and relax in the shade. :D It's good to be retired!
     
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  11. gmorider

    gmorider TrainBoard Member

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    rray, I am amazed once again. Well done. I read the entire thread even though I do not model this scale. Fascinating stuff. :cool:
     
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  12. husafreak

    husafreak TrainBoard Member

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    I just posted this as a link for another modeler on the AZL forum. We all love a creative solution. I've become a big fan of your work!
     
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