NW-Modeling-List Digest, Vol 70, Issue 5

NW Modeling List nw-modeling-list at nwhs.org
Fri Oct 9 19:24:24 EDT 2009

Mark: Something is loose or mis-aligned..duh... Seriously, take the
shell off and look at the gear meshes. If it loads up heavily UNDER LOAD
and then speeds up without load (going down grade) it is likely that the a
gear mesh somewhere is either pinched together - no backlash in one
direction of rotation- or too far apart. I do not know about this model's
transmission style, but a worm drive where the worm is shifted fore-or-aft
over the worm wheel or is spaced too high above or too low, taking out all
of the backlash, will cause your sort of problems.

Backlash= the space behind the meshing gears where the driving gear tooth
rolling out of mesh from the driven gear clears the driven gear tooth to the
rear. You gotta have some backlash or the backs of the teeth cut away the
opposite gear.

On a worm gear, moving the center of the worm wheel 'up or 'down' away from
the centerline of the changes the backlash. Also, shifting the worm away
from or towards the worm wheel will change the backlash too. This is
changes by adding or subtracting shims behind the worm wheel. Up and down
requires mounting corrections.

Drivers out of square (opposite pins not at 90 degrees) and oversize rod
bores can cause similar binding/no binding situations.

Loose motor in its mounting is a possibility too.

Gary Rolih



From: nw-modeling-list-bounces at nwhs.org
[mailto:nw-modeling-list-bounces at nwhs.org] On Behalf Of NW Modeling List
Sent: Friday, October 09, 2009 7:41 AM
To: NW Modeling List
Subject: Re: NW-Modeling-List Digest, Vol 70, Issue 5

The J I have is only a year old. The engine won't pull more than 8
heavyweights up my 2 percent. The big problem is that coming down the other
side it speeds up and the mech freezes, stalls locks, up or some such. I
have the "in service" version with the dual side rods between 2 & 3 drivers.

Mark Lindsey
Stuck in the 1930's

On 10/9/09 2:28 AM, "NW Modeling List" <nw-modeling-list at nwhs.org> wrote:


Which version of the Bachmann J do you have? If you have the original
Bachman J, then I agree with your assessment of the mechanism. Bowser used
to make a replacement chassis for them. If, however, you have one of their
recent (relatively) Spectrum J models, then I disagree. I think Bachmann
did a fine job with that model. Early ones had some problems with the
trailing truck mechanism causing derailments, but that was easily fixed.
Mine run superbly, and I installed either Soundtraxx DSD decoders, or
Soundtraxx DSX sound decoders with TSX motor decoders. Both work superbly,
although, I know that the newer Tsunami would work even better, but I'm not
changing them. It is easy to fry the lights, but also easy to fix.

Kert Peterson
Fircrest, WA

On Thu, Oct 8, 2009 at 9:00 AM, <nw-modeling-list-request at nwhs.org> wrote:

Date: Wed, 7 Oct 2009 18:18:48 -0400
From: NW Modeling List <nw-modeling-list at nwhs.org>
Subject: Re: Soundraxx Southern Steam decoder into a Bachmann J DCC
ready Ho loco
To: NW Modeling List <nw-modeling-list at nwhs.org>
Message-ID: <4DA6E4E2-E8FA-4506-AB24-4B0C0D6A415D at earthlink.net>
Content-Type: text/plain; charset="us-ascii"; Format="flowed";

The decoder might be set up for 16v lights? Just guessing. I fried
my J's lights with a Soundtraxx Steam decoder from 2002? era. Sounds
great, but I cooked the LED lights. I'l re-visit the lights with MV
lenses and Grain-Of-Dust lights.

I hate my Bachmann J because of the wimpiest mechanism I've even seen
in a 'modern' HO steam engine.
I'm seriously looking at Gutting it and putting in a real motor and
NWSL gearbox.
This all depends on axle diameter.
My Brazelton "Auto-Quarter" is for 1/8" axles and slightly smaller
Brass imports size.

Mark Lindsey
Stuck n the 1930's.

On Oct 6, 2009, at 3:56 PM, NW Modeling List wrote:


I have fitted the above decoder into my Bachmann J which previously
had the DCC ready decoder.

All works well and I am very pleased, but, the lights don't work. The
generator sound comes on but no lights on the loco.

Any ideas please?

Many Thanks

Barry Reeves
Songwriter & Musician
www.northwestlondonblues.co.uk <http://www.northwestlondonblues.co.uk/>

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