I purchased a Challenger 3985 with Tsunami Sound (4-6-6-4 N Decoder) or the previous release with Tsunami 2009 I believe. However the issue I'm having is that the locomotive seems to have some kind of short that constantly keeps resetting the locomotive when attempting to run. When stationary on my DCC layout the locomotive works fine. The headlights sound etc respond to my throttle with out any problems. It is just when I try run it is when the trouble of shorting out begins. The locomotive will not move one inch down the track with out immediately resetting and shorting out dead. Even on DC power the engine still shorts out on me. I never had the problem before until recently. I have cleaned the wheels, cleaned my track, checked for dead spots, and checked for loose wires on the engine but I just can not figure out what is causing all the shorts. Any suggestions before contacting Athearn?
My first purchases of Athearn Challengers, when they had the MRC POS decoders...and I was shortening the drawbars on all of them, yielded the fact that two out of five Challengers had one of the speaker wires squashed between the tender body and a metal mounting peg on the decoder mount. I'm not sure if that would cause a problem for the TSU decoder, but it might. If everything runs okay with the tender body and boiler top and cab off, you know you've got a pinch somewhere...most likely in the tender. However, there are some wire bundles in the engine chassis under boiler top casting that could be either pinching or rubbing on the chassis or flywheels. Might as well open it up and take a look. Another potential problem area is the DCC plug in the tender...ya gotta have the tender shell off to look at it...another reason to do just that. I think once you get the guts out in the open, you'll find the prob a lot easier, and tender body and top boiler/cab shell are pretty easy to take off. I'm betting it's just one wire somewhere that's been pinched and is shorting on the frame, or a wire that's a cold solder joint and when the engine moves, it breaks contact...engine stops...it regains contact....engine moves...it loses contact. Good luck! Cheerio!
Is it literally shorting out or is it just losing conductivity (power comes and goes)? If the former it could be that the decoder is failing. If the latter, I'd look around for bad wiring as Robert suggested. Cheers, -Mark
I think it's your decoder. I had the same exact problem 2 weeks ago. I had the MRC decoder in it. The thing ran great for all the months I had it then out of no where two weeks ago boom short, short short every time. I took the thing apart and removed the decoder and put it back on the track no shorts, so I concluded it was the decoder especially from reading around on the forums that this was bound to happen. Your only alternative which is a PIA is to install a Tsunami TSU-750-heavy steam. The other recommended drop-in replacement for the MRC has already been discontinued.
Thanks for the tip. I have checked everything and reassembled is it working better now. Only small issue that the short seems to be the pilot truck on the centipede tender.
I'm gonna buy a shovel cause I keep digging up old threads ........... sorry. So my dad's Athearn Challenger was running great and then the next time he went to run it ..... nothing. Our club track was indicating a short circuit each time the loco was placed on the rails. I have managed to get the tender rear and body off despite the videos available on Youtube. If anyone was wondering remove the 2 screws under the back beside the coupler and the rear comes off. The main body of the tender needs to be spread a little and pulled backwards essentially sliding it off the back of the centipede chassis. I would like to know how to get the front of the tender off ..... would anyone know whether it goes forward ? .... upwards ?? ... or what? The red wire appears to go nowhere and looks to have never been connected....... should it be connected to anything ? I have found a little bit of bare wire immediately above the speaker. I've moved the board and wire away from anything but the loco does not respond to anything and DecoderPro does not identify the loco. I'm using a Sprog 2 on a programming track.
You are welcome to revive any open old topic. From past experience, there have been some very interesting additional discussions.
308GTSi, Thanks for digging up this old thread. I am going to post 2 images that I made of an Athearn Big Boy that I purchased new from their last production. It was an analog DC loco that I planned on adding ESU LokSound decoder. Guess what, brand spanking new and it should run well out of the box, right? Heck no it did not run well at all as a new DC unit So I stripped it down and here is what I found. Keep in mind this is fresh out of the box, manufacturers work : #1 - shows the innards of the tender. Note the very nasty soldering, actually the two clumps of solder were very close to touching and maybe did as heat expanded them. I took my #11 blade and widened it. Also note that there was a plastic retainer (?) that was melted while working in the area. Real neat stuff! #2 - I removed the boiler shell to check out wiring. Guess what, I found a possible problem. You can plainly see the orange motor wire. Where is the black wire? It was "hanging on" by 2 strands of the wire. Real neat stuff : I have ragged on Athearn enough but I have not nor will I purchase anymore of their stuff. A purchaser should not have to fix a mess like this. To be fair, I never contacted Athearn regarding this problem as I figured I could fix it easier and faster then they would. PS: It runs like a KATO now, well almost. Have a good one.
Maybe an antenna wire for the remote that used to ship with the early versions? It was for getting sound on DC layouts. Just like BLI has “antenna” wires on their Rolling Thunder-compatible locos.
Dad feels that you are correct. So we can establish that this loco is one from earlier production then.
Wow , that really is horrible wiring / soldering ........... almost like I was in charge of the electrical dept that day. .. LOL Working on DCC is not my favourite activity ..... I hesitate at time ,,,, just ask Sumner , he's been trying to help me with a Con Cor Turbine. The first thing I noticed was the wires are all the one colour in this loco (black). It reminds me of a Vertical Borer (made in the USSR) I used to run at work years ago .... it had hundreds of wires in it ..... all red !! Anyway I have just been working on the Challenger and it appears this one has a fault caused by workmanship at the opposite end of the scale ...... everything is far far too neat. Dads loco appears to have the tender pickup contacts too close to the screw that holds the plastic retaining cap in place. I shall get a small round needle file and increase the clearance beside the screw. I'm going to use a tiny bit of Krystal Klear to sort of glue the contacts in place before adding the retaining cap and put the screw in.
One place to look for a short is the front tender truck. When my 2017 release Challenger was new out of the box, it would sometimes short going around curves. On close inspection, I found that the solder tabs (and horrible solder job) for the pickups from the front tender truck could be "bridged" by the truck spring, causing a direct short across the truck. When I swapped decoders, I trimmed the solder tabs, rewired the truck, and then slathered on some liquid electrical tape for good measure. I don't have a BEFORE pic, but here's an AFTER pic: I ended up pretty much re-wiring the whole thing, tender and loco. Another issue I had that appeared a year down the road... As the loco ran, the motor brushes wore down, creating a TON of rusty-colored powder in the motor housing. This gunk accumulated and eventually shorted out the commutator in the motor, pretty much requiring a complete replacement (Altho' I cleaned the gunk out, Athearn did not have spare motor brushes, just spare motors). The "new" motor was from a previous release, and (so far) does not appear to have the same problem. Been running fine for a couple years now...
