Athearn Challenger (1st Run) Disasembly guide (& bulb replacement) Big Boy too?

[Tom4884]

THANK YOU !  I have a first run Greyhound with a bad decoder,  this is exactly what I need to get it replaced.   Great work!

Tom 👍

[u18b]

THANK YOU !  I have a first run Greyhound with a bad decoder,  this is exactly what I need to get it replaced.   Great work!

Tom 👍

I'll add more with pin-outs of the plug.
And how I repaired broken pick-ups in the tender.

[ATSF_Ron]

Ron, thanks for all this!  This is great documentation and easy to follow.  I have a 3rd run (I think?) challenger in NP.  Everything has been fine so far, but you never know!  This will be a HUGE help should I ever need to open it up!

[u18b]

Pete is correct.   These magnet wires may not be best.   They've lasted a couple of years, but they might fail one day.    When I did this years ago, I did not have really thin stranded wire (I mean REALLY thin).   

But since then, I bought some prewired 0402 tiny LEDs off ebay from Asia and WOW- the wire is small.   When I install an LED, I SAVE the wire because it is so thin.  So one day I may use that to replace these wires.

[u18b]

OK.  Decoder time.

To get in the tender.
On the bottom, remove the two screws at the back end near the couple (you may leave the coupler alone).

Top side, remove the coal load (it may be tight).   You can usually lift at the purple arrow in the corner.

Then remove the rear-most hatch.  Try to pull straight up or you may brake a mounting pin.

You can now see the two screws you must remove (yellow).

Then lift the rear just a bit (blue) and then slide the shell to the rear (red).




I don't have a photo of my dead decoder.  So here is a photo I borrowed from Spookshow.
This is a Tsunami decoder and I think this is what mine had.

At any rate, there are two plugs- one in the front (blue) and one in the rear (red).
The front is the locomotive main harness, the rear is the speaker wires.




Here is the bare tender without the dead decoder.
Direction is now reversed- the speaker wires are clearly the red and black pair.



The plug we care about right now is the one up front.   We can hot-wire this for analog operation.   The pin-out follows typical practice.   The outside edges is track, the next two inner are motor.   The lamp is center.   This all corresponds to the five pads up on top of the boiler in front of the cab on the circuit board.

I have color-coded these for std DCC.
NOTE:  the Lanp wire is actually the white decoder wire.   I connected the positive blue wire to the magnet wire. 



To get this to run analog, just jumper the two pins on the outer edges (black-gray)  and (red-orange).
But I like to make a decoder removable sometimes.   This helps with testing in analog.

So I took some TCS micro 2-pin pugs and sockets (removing the wires).   Kind of expensive, but it works.
https://www.tcsdcc.com/product-page/2-pin-micro-connector-black-and-white-wires

Here, the TCS plug (with the posts tinned with solder to make them a bit fatter) fit perfectly.



I then place a socket on each pair.   By soldering the tips of the socket- we are making a jumper (bottom).   I then heat shrink to prevent shorts.



That's it.   With those pins jumpered, the locomotive runs in analog mode.

[u18b]

A decoder was easy at this point.   

I originally mounted a TCS decoder to a spare Kato analog light board for an F or E unit.
You can see that the white wire goes to the center of the plug.   The resistor on the board is for the rear LED.


 
Underside.  Notice I mounted 2 TCS sockets that will fit on those plugs shown above.



About 3 months ago, I removed the DCC and added a ESU v5 Nano for sound.   I loaded the Big Boy sound file.
Notice the blue wire goes to that extra magnet wire I ran to the tender.





I chose this kind of setup so that I could mount it with a screw on top of the middle post and letting the end post pass through the board.    This also allowed the rear LED to be at the correct height.



So I now have my sound equipped Challenger back!

Next time, I'll show how I repaired the electrical pickup in the tender.

[u18b]

Well, the Athearn Challenger had some problems when they first came out.  Something about shorting.  And they offered replacement wheels.
Since mine was used, I have no idea if I have original or replaced wheels.... but I do know that one day when running it died.

The decoder was shorted out.

Now usually, a red/black short is inconsequential and a decent DCC system should shut down with no problem.   So I don't know what happened to mine.

But when I dug into, what I found was disturbing.

There are two weights that must be removed. 
The first is in the rear (right in this shot) of the tender.  Just lift it out (with no decoders in the way).




You then have to remove the speaker.  It is retained by two screws with bent washers to hold it.




With the speaker lifted out of the way, you can see the retaining screw in the sound chamber.




While you have the weight out, flip it over.  There is black insulation tape in that slot.  Mine was old and moving around (not good).  It might need to be replaced.




When I removed the rear weight, I was floored.  The electrical pick-ups were trashed.
Two wiper tabs were broken off (blue).
One was bent and not touching anything (purple).
And something bad happened and melted the plastic position-er/cover/insulator (red)!



And the ones under the speaker weight weren't much better.   The wipers were on TOP of the wheels instead of behind them.   I'm guessing someone had removed the wheels from the bottom of the tender and replaced them without thought to the wipers.

This was all bad.   I had repairs to do.   Obviously, that screw holds the cover plate on.



The wipers are in two halves.



But mine were so damaged, they fell apart.  They are VERY delicate.



Here's my melted cover plate.



When you remove the wipers, notice the insulting tape under the solder joints.   You don't want any shorts if this is gone.

[u18b]

I needed to replace the fingers that wipe the back of the wheels.




I had some VO-1000 pick up strips.  I drilled holes in one end.




I then soldered them to the broken pickup.






I then trimmed and bent them.



When I had a pair, time to re-install.  That's tricky because you need 3 or 4 hands.  Here's how I held them in place while reaching for the cover plate and screw.   By the way, notice that the black insulation tape is in place under the solder joint to the wires.




Cover plate installed.  Now since my new pickups were beefier, they were also stiffer (too stiff).   I had to bend and test them until all was just right.



After repairing the other pair, I was good to go.

This is one of my favorite locomotives.   Glad to have it running again (with sound).

Hope this all helps folks.    This concludes what I did with mine (so far).