2-6-6-2 drive problems.

[robman]

 Hi there one and all. I recently purchased a 2-6-6-2 Bachman artic (new)through a web site here in NZ and it has developed a drive problem. When under load, if slippage (wheelspin) occurs, only the rear driver set slips while the front set just stops. I assume that the universal to the front drive set from the motor must be slipping on the output shaft.
I did pull the loco down as far as loosening the weight above the motor but wasn't too sure if this was the best way to access the drive shafts  inside.Has anyone pulled one of these apart and what is the best way to go ahead. I am generally capable of doing all my own maintanence but I don't want to screw this up. Any help would be really appreciated as Bachman service centres in NZ don't exist to my knowledge. Cheers for reading,happy modelling and stay on track. Cheers Rob.

[robman]

  Hi there one and all. I didn't get any replies to my reqest so I suppose that no one has had to pull a 2-6-6-2 apart yet. Well I have, and what an interesting find. The cause for the lack of traction from the front drive set was not the plastic universal on the motor output shaft, but instead was the small metal driven knuckle on the shaft which has the worm drive on it.
  I also found that the plastic snap cover over the front worm drive was not seated properly and was cracked, poor assembly, but I was able to fix it up and now it runs great. I have noticed a few other owners of this loco say that it hasn't the pulling power you expect, well mine has now so maybe a stall test to make sure that all twelve wheels are driving may show up the same problem that mine had. Cheers from Kiwiland. Rob. 

[GN.2-6-8-0]

Glad you got it sorted out Rob,I've got the Bachmann 2-10-0 Russian Decapod and was a bit leery of pulling it apart worrying about the thing being overly delicate.....This from a guy who wouldn't think twice about totally dismanteling a brass Great Northern articulated to put a nice looking ( my opinion) paint job on it....

[SteamGene]

Brass is much simpler to take apart than modern plastic/metal.
Gene

[Rickmartin]

Been looking for the same answer myself. My 2-6-6-2 which has never been run on a layout, just a long test track has the same problem. The front engine runs but the rear one does not. I've looked at the parts diagram and I can see that removing the dome between the sandboxes exposes a screw. I assumed removing that screw would free up the boiler but it doesn't seem to do anything. I'm kinda old school about my models and prefer to do my own repairs. Have zero problem stripping a brass loco and repairing or painting it but I find that most of the new plastic/metal rtr stuff needs a degree in engineering just to get it out of the box. Has anyone found the secret to exposing the motor and gears on this thing. Sure would appreciate it. I'm a real cheapskate, and don't want to wreck an expensive model while trying to repair something that really shouldn't need repairing on a new engine........Rick Martin

[SteamGene]

You have to remove the cab before removing the boiler. 
release one end of the cab grabs. 
With a small straight bladed screw driver, release the tabs at the bottom of the cab and lift it away and off the locomotive.
Access and remove the screw in the sand dome.
Slide the boiler up and forward.

Gene

[Rickmartin]

Gene: thanks for the info. I thought something else had to come off before removing the boiler. Appreciate the words.  RickMartin

[SteamGene]

Welcome.
Gene

[Isambard]

The Grizzly Northern's newest acquistion, a very smooth running beautiful Spectrum 2-6-6-2, unexpectedly stopped running at the recent Exporail (Canadian Railway Museum)  miniature trains weekend. Total running time since received from MicroMark is less than 10 hours.

So far  I've determined that in programming mode the DH123 decoder responds to address changes. In ops mode the loco headlight functions, but flicks on and off with the command station/PM42 reacting to a short circuit. Visually the loco and tender appear normal and the decoder and tender wiring appear normal.

My next step will be to change the decoder and see if that changes behavior, if not then to test without a decoder using address 00, before I attempt any disassemby. I'm concerned that I may have stalled motor and certainly don't want to cause any damage.

In the meantime any comments will be appreciated, as always.   

[robman]

 Hey guys, Sorry i didn't see these messages sooner but I've been away working (got to pay for the trains somehow). Rick, I hope you got your 2-6-6-2 fixed, it seems that you may have the same problem that I had, check that knuckle drive on the other end of the worm drive shaft. my one appeared to be tight but with just a little pressure was in fact loose. I presume that you got your loco apart but if not this is how I proceeded.
1st the screw under the dome then the cab. The next step after taking off the boiler was to make a diagram of the PC board connections (I did this inside the box lid ready for next time so I won't loose it) then I carefully pulled the wires off the board and slid them through the cast weight. Undo the two screws and lift of the weight and presto, there you are.Upon first inspection chesk that the saddle clamp is seatted properly  and not broken as mine was. Hope this helps, stay on the rails Kiwirob.

[Isambard]

The Grizzly Northern's newest acquistion, a very smooth running beautiful Spectrum 2-6-6-2, unexpectedly stopped running at the recent Exporail (Canadian Railway Museum)  miniature trains weekend. Total running time since --------------------------------------

It proved to be a decoder problem and not a loco one, hurray! I swapped the DH123 decoder from the 2-6-6-2 with a DH121 from a 2-8-0 and found that the 2-6-6-2 now ran smoothly and the 2-8-0 indicated a short circuit, with a buzz coming from the DH123. I'll send the decoder back to Digitrax to see what they have to say about the cause. I've since installed a new DH123 in the 2-6-6-2 and at the same time removed the RF suppression capacitor from across the motor leads.

As a comment about the decoder PCB in the 2-6-6-2, it appears rather like a lashup, maybe a warranty return fix? The PCB is loosley secured at the rear end only, via a small screw to a support pillar. A generous coil of unsecured wires leads from the PCB to the connectors under the loco cab through the rectangular hole under the tender coal shelf. Has anyone else found the same installation? It works and I'm not worried, just curious.


--------------------------------------------------------------------------------
Isambard

"Grizzly Northern Railway - The Running Bear Route"

http://www.wimrc.ca

[Atlantic Central]

Isambard,

The mounting/wiring you discribe is just like all seven such tenders I own. I doubt yours was touched by anyone other than the factory until you did.

Sheldon

[ronronbo]

I can't get the top off of the boiler, i only found the one screw on the boiler.

[GN.2-6-8-0]

Did you remove the cab?