CN GP38-2W
#1
Hello,

in 2019 i had the chance to purchase 2 Athearn Genesis EMD GP38-2Ws in CN stripe livery out of an estate:

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Unwrapping the locos appeared they were unused, like new and came with all papers. Both were DC analog.
Both had still the traditional wheat of grain incandescent 1,5V microbulbs. (Glad Athearn has run out of stock with this stuff and is now forced to install LEDs instead Big Grin )




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My intention was to convert both of them to DCC with sound.


Lutz
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#2
Hello,

loco #4789 was done at first:
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Do the usual practices, unscrew and remove coupler boxes at first. The gently pry the shell off the frame.
This is an older motherboard with 2 interfaces, left the 8-pin interface as NMRA S-9.1.1.1 and in the middle the JST 9-pin interface as NMRA S-9-1.1.2. Many decoders in the US have already a JST 9-pin plug fitted, removing the analog plug and instead plug in the decoder is the simplest way to convert to DCC.
But because i selected my decoder in PNP implementation, the motherbord has to be removed.




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This was done here. There a no soldered joints, by removing the plastic retainers the wires can be easy pulled out.
Then clip out the motherboard.




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Athearn uses a special motherboard with voltage stabilizers für their 1,5V incandescent bulbs. These are not suitable for LEDs.

But here i have more ambitious efforts concerning of reliable running like a dream.


Lutz
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#3
It looks like that locomotive should be a pretty decent puller, as there seems to be a fair amount of weight.  The best part to me, though, is that it's wearing one of my favourite paint schemes.   Applause Applause Applause

Wayne
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#4
Hello,

@ Wayne
Wait a little bit, because i removed one of the weights permanent.


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By loosening 4 screws the additional weights came off.




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Pry the worm covers.




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Lift the worms and universals out.




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Then lift the main frame off the trucks by 0-5-0 crane.




The tricks to disassemble this type of trucks:

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1. pry off the botton gear cover.  There are 4 snap on loops at each cover. The material is very flexible and for this the danger of tearing them off is very minimal. You can see on the photo there are also 4 lock bars which hold the truck sideframes into place.




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2. When the bottom cover is demounted, you can easily pull the truck sideframes.




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3. Remove the other sideframe and take out the wheelsets.




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4. Unscrew the 2 crosshead screws, one at each side of the gearbox and the halves will come apart.

As you can see, this is a dry zone, devoid of lubricant. Of course, there is lubricant applied in the factory. But as in most cases i have seen, the gear grease is sitting scared in the backstage and here at this place it is simply useless.



Lutz
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#5
Hello,

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A closer look into the shell. A lot of black wires ending in micrro incandescent bulbs. These will be replaced by LEDs.




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An oversight of the demounted running gear.




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Starting with remowing the micro bulbs. Here one of the ditchlights is gently pulled off.




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The micro bulbs are glued. But fortunately  the glue is water soluble. So i applied some water with a handbrush and give the water some time to affect the glue.




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Pay attention to the tiny light glasses. They are also glued with this water soluble stuff. Pick them up with great care and store them safely.




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After a certain induction period the bulbs can simply pulled out without any resistance.


Until now only the demounting of the loco is described as preparation for the modifications.


Lutz
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#6
O.K..

lets start to rebuild this thing.

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Controlling all wheelsets if they are comform to NMRA Standards.




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An investion into the future. As long the parts are shiny new and clean, the current pick up is flawless and reliable. But as the loco accumulate mileage, catching some fibers oder get some oily, the dependability sinks and the loco became running stuttering.
Of course, you can demount the trucks and cleaning all parts, but how often you are willingly to do so?
My solution are additional wipers made out of 0.3mm bronze wire. Pieces of them were soldered onto the inner brass frame.




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Before reassembling the gear boxes, distribute the grease to places were it really is of avail. Here the the studs were the spur gears are pivoted. Then reassembly the gear boxes.




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Choose one of them, i usually take the front truck. A stack of washers is piled up just to the height of this pair of nubbies onto the the main frame will be beared.
The other truck remain unaltered.




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Take this stack of washers and pile it onto the kingpin one one half of the main frame. Fix it by glueing with CA.




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Take a good side cutter and crop off the nubbies of one truck. The other truck will be unaltered.




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Reassemble the trucks further. The excess length of the new wipers will soon be cutting off with a wire cutter.
Then reassemble both trucks onto the main frame.

You now have loco with a selfmade 3-point suspension.



Lutz
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#7
Hello,

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The new LEDs for the lights. The tower type 2mm warm-white LEDs are for the headlights and will get 1.2Kohm resistors. The abbove shown type 0603 LEDs are sunny-white and pre wired. They will get 1.0Kohm resistors.




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But before installing the LEDs get some black dye and brush a thick layer onto the inside of the shell. Otherwise you will have the illuminating effects of Rudolph the red nosed reindeer.




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When the paint has dried, i begun mounting of the LEDs. First the ditchlights, but the wires here are somewhat tricky to manage them around some sharp corners and through small bores.
One of the tower LEDs has bee places also.




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At the rear end of the loco there were no ditch lights. But because i wanted them here too, i purchased a pair of EMD standard ditch lights from Details West. Also the LEDs and resistors were ready placed.




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Because the Details West ditch lights were not intended for lightning, the casings were drilled out by the means of a 1.5mm drill bit.




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Then suitable bores were drilled into the rear deck and the ditch light casings glued onto. For the ease of handling the light casings during mounting them, the sprues were removed when the glue had hardened.




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Wires, wires, wires. For deconfusing me the colours were in accordance to the NMRA guides wherever it was possible.




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Each LED has it's own resistor. The colour codes tells you where the wires run to. Only the ditch lights have black wires, because they were delivered with them.




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So it is not really an big secret.
BLUE = decoder "+" 12V, one wire of each LED, the "+" one of course, lead the the "+". The decoder has 3 "+" outputs, so simply choose one. The BLACK "+" wires of the ditch light LEDs terminate here also
WHITE = front light, here the resistor is interconnected
YELLOW = back light, resistor too
BLACK "-" of the front ditch light LEDs terminate both at an resistor which is soldered to F3 output
BLACK "-" of the rear ditch light LEDs terminate both at an resistor which is soldered to F5 output

That is the whole magic of wiring your loco.
As the front ditchlights on CN locos are only both ON when the loco is moving, they can be terminated both to one decoder function output. The same is just with the rear ones.

The next magic is function mapping and configurating the decode function outputs.  For this RTFM! of your decoder.


Lutz
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#8
Gotta hand it to you, Lutz - you do a very thorough job when you re-work your locomotives. Worship Worship Worship 

Wayne
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#9
Hello,

@ Wayne
What i want are locomotives which will run like the prototype and that as hassle free as possible. These modifications of running gear, current pick up and other of these little improvements are a part if it. Running my locos in DCC mode with sound is a further aspect of it. Another objective is the prototipical look. Also these improvements of track and turnouts, like live frogs, are part of this goal.


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When all wires were sucessful stashed under the shell and the shell itself can be put onto the running gear without any force you are the winner. Function check ride for the lights.




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The ditchlights were painted matte black.




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The lenses were glued with the aid of Micro Crystal Clear.




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The next day the Crystal Clear has dried and became clear.



Lutz
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#10
You have done a great job and I admire that   Applause   Worship   Thumbsup                             
but if I had to do that to get a loco the way I wanted it I would leave the hobby and never return.  Big Grin
but that is what makes this a great hobby, you can do whatever makes you happy regardless of how someone else enjoys it.
Mike

Sent from my pocket calculator using two tin cans and a string
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#11
I am speechless.  You have done a tremendous job.  Last year I bought an Athearn Genesis GP9 which revealed itself a bad runner due to bad power pickup. My trackwork is not perfect but all my other locos run well even on Atlas turnouts.  I had a Proto 2000 S-3 which had bad power pickup even when running on DC. On DCC it was a nightmare.  I have done like you did and added some extra wipers.  It solved the problem.  But it was a lot easier to do on a Proto 2000 than on a Genesis.  I would certainly not try to completely disassemble this loco to add wipers. It's simply beyond my skills.  I'll never buy any Genesis locomotive in the future.  I simply can't understand we can send a helicopter to fly on Mars, but can't build a locomotive model with good power pickup.
Guy from Southern Quebec.
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#12
Guy,

some tips:
For only adding wipers you don't have to disassemble the whole loco.
Pry off the bottom cover of the trucks by a small screwdriver. And don't worry, the plastic material is of high quality and very elastic and for that not prone to break.
Once the covers are off, you can pull the truck sideframes left an right. The wheelsets can be lifted out, clean them thoroughly at this occasion.
Further you can pull the plastic caps which clamps the wires. Then the truck frames are separated.

Points of attention for remounting:
- Very fine details on the shell; for this it will be better the shell has been lifted off before.
- the truck sideframe with the cable for the speedometer have to be mounted under the engineer's side of the cab.
- Pay attention to the plumbing of the air reservoirs when remounting the shell. They should be fit under the skirt of the running board.


Lutz
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#13
Lutz,

Thank you for the detailed instructions.  I might give it a try in a near future.  It sounds simpler than what I expected reading your thread.

Many thanks.
Guy from Southern Quebec.
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