Kumata brass E/E1/E5/E3/E6 Rebuild Project w/ DCC & Sound KMT

[u18b]

Beautiful... I'm still learning this hobby, and trying to figure out the best way to add DCC/Sound to a DC E6/E8/E9 Illinois Central pair. But your thread provides hope. Thanks.

Thank you.
These are great locos when properly adjusted.

[DanielC]

Just saw this thread.  I got a Kumata RS-1 recently.  My problem is not short but open.  If I secured but front and rear shell screws, it won't run.  I have to left one screw off and it runs fine.  Any idea what I need to do?

[u18b]

After selling the previous pair, I snagged another E1 set at a really good price.
I'll probably keep this one.   Time to rebuild.



I followed the basic steps as before in rebuilding this set, but made a few mods based on the knowledge gained before.

Here is the A chassis without the weight.  You can see the following:
Both gearboxes are insulated so the frame and shell are not charged (reducing shorts)
Flywheel added with Atlas hex nut interface.
A new u-joint on the right which i saved from an old 1970's locomotive (every original u-joint was cracked).
black shims are installed to raise the shell just a little.
Also, the bottom of the frame is taped to prevent wheels from shorting on the frame.
Loco has also been Beardenized with no inner bearings on the worms.
The soft steel wormshafts have been replaced with stainless steel tubing cut to needed length.



Here is a close shot of the missing inner bearing.  All it needs is the outer bearing and friction and noise are reduced.




Here is the chassis with the weight installed.   This is now rebuilt in analog mode.  Runs very very well.

[u18b]

I then added sound.

Rather than step by step as before, I'll just show the finished product.
And note the changes from past experience.

My first set used an ESU Nano with the NEXT18 interface and space was REALLY tight.
Now that the Nano comes in an E24 interface, space is much more reasonable.
The Nano lays flatter.  I can also pop it out if I want to run the loco in analog mode for repairs or tuning.



You'll notice this project looks a lot cleaner and simpler than before.

Here is the front headlight board.   Instead of supergluing the board to the gearbox, I drilled and tapped the gearbox and secured the board with tiny M1.2 screws.



The board over the motor is secured by the motor tabs themselves.  You can see the DCC color coding.   The red wire is the jumper from the front gear box which is right rail only.

The rear board is much cleaner now.    I used a six-prong socket instead of two sockets as before.
You can see that I drilled and tapped screws for this board also- but I realized that I can draw power through these screws with no jumper wire.  So I drilled on the left side of the gearbox since this rear gearbox is the left/black rail.

So on the board, from top far side to bottom near side you see:
black- sending power both to the B unit by socket but also forward for the decoder.
gray motor
green speaker   (remember that if you're going to run two speakers, they must match polarity- thus the green wire).
brown speaker
orange motor
red




And lastly, I cut the channels for the wires a big larger than before.   Once again, since I broke thru the chrome plating, I sealed it back with solder.

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This is the back of the A unit.

Here is the MU jumper for the B units plugged into the socket.

This is much cleaner and secure than before.

[u18b]

And here is the B units.

Once again cleaner than before.

Notice I added the stock weight (with the tops edges trimmed).   I made a little two channel circuit board inside for running the speaker wires.




Here is the front circuit board, screwed to the right side of the gearbox (red/right rail).
Notice the speaker wires in the center.   The circuit comes from the A unit plug and then goes down to the little board in the weight.




Here is the coding for the front board.




Here is the rear of the chassis.
This far back, I don't need the red wire anymore. 
However, I do need the black wire- this the board over the rear gearbox to send left rail power forward.
Speaker wires run under the motor as before.

[u18b]

I used a slightly shorter drawbar and the results look good.    From 3 feet, there is only a small gap.



This set was slightly damaged.   One of the rear steps had broken off the B unit.    I replaced it with a similar step from a Gold Medal Model stainless etched set.   Not perfect since it is just a little smaller than the stock steps- but looks much better than no steps.




As an extra touch, I closed the front coupler pocket per the prototype.    I used a framing on a GMM stainless etching.   Then bent and filed until it fit reasonably well.   Not perfect but pretty good.   I may go back and add some black stripe decal for a louver effect.




This set is really amazing.    Kumata locomotives do not have a great reputation.    But when you know how to tweak and mod them, they become outstanding.
This set runs as smooth and quiet as a Kato locomotive.
Since the A and B unit are electrically connected, each rail draws from 6 wheels each (instead of 3 formerly).    So no stalling and with no keep alive.   One decoder runs both units.

And nothing can beat the chugging sound of the ESU decoder on an early diesel.

[u18b]

Here's a little bit more.

For the blue and white LED wires, I installed a socket under the board with a plug.   This makes the board removable if needed and cleaner from wire clutter.



If there is ever a problem, I can remove the ESU Nano.
To run the loco in analog mode, I made a plug for the rear.  The middle pins are missing (speaker wires).  And the outer pins are jumpered (red/orange   and   black/gray).






Orientation does not matter since it is symmetrical.



I also made a jumpered plug for the B unit.





And lastly, the LED addition is a nice touch since the model comes with no lights.