NW-2 board

[Joetrain59]

 Hi. Does anyone have a PC board from a N Bmann NW-2 they could sell/spare?  Took mine from it's box the other day, and running was sketchy. Soon realized rear truck not providing power. Took shell off, check wiring to truck, cleaned/adjusted wipers. Tried testing it on bench with Kato power pack and wasn't having much luck. Tried putting power to where truck leads are soldered into board. Nothing. Tried power leads at motor wires on PCB, and got some smoke.    Loco runs, but not in "reverse", cab end forward. Too many/too much wire on this loco. Have another, runs like a dream, as this one did when new.
 Joe D

[peteski]

Joe,  does that loco have the factory-installed DCC decoder (on that board)?  If you apply DC power directly to the motor lead you will smoke the output transistors of the decoder!    There are 4 transistors (2 for forward, 2 for reverse). If it runs in one direction it looks like you smoked at least one or two of them.

[Joetrain59]

Guilty as charged.    I'd like to lose that Bmann board, but keep the lights. More room for weight then, perhaps.
 Joe D

[djconway]

Feel like a project?  Try the Digitrax DZ126T decoder - its a hard wired install but should be doable.

[Joetrain59]

dj, I run DC.

[SP-Wolf]

Perhaps the DC light board from a Kato NW-2 would work-?

Just a thought,
Wolf

[mmagliaro]

I would keep the Bachmann board, since it fits and it has the lighting LEDs in just the right places.
Just cut the traces and bypass the decoder. 
You might need dropping resistors and protection diodes for the lighting LEDs.  Power has to be coming up from the wheels/frame onto that board, so find that, cut the traces, and route
around the decoder entirely.

[peteski]

The LED resistors are already on the decoder board - you just need to track where they are and cut the traces in the correct place to keep the resistors in the LED circuits.

[Joetrain59]

Thanks Max and Pete. Now I'll just have to do some detective work to find which traces to cut. Never cut one before, so what's a good way to do the cut?
 Joe D

[peteski]

I either use a cut-off wheel in a Dremel tool (at slow speed) to grind through the copper trace (don't breath the dust) or score repeatedly with a hobby knife (in 2 places) then pick off the sliced off piece of copper.

[mmagliaro]

I either use a cut-off wheel in a Dremel tool (at slow speed) to grind through the copper trace (don't breath the dust) or score repeatedly with a hobby knife (in 2 places) then pick off the sliced off piece of copper.

I would vote for the Xacto. 
Once I score through with the Xacto a few times, I usually switch to a narrow triangular jewelers file and just saw
away at the little score until I get through the trace.  I find it easier to get through the trace with a file, rather
than the knife.  The file also makes a little wider gap between
the two pieces of trace, which makes me feel better than the tiny slit cut through there by an Xacto.

[Joetrain59]

Haven't had the time to get back to this job. Did work on GF's car Tues/Wed, and now she's down with the flu. Have to handle all the chores here. By time I feel like working on NW-2, I'm beat:(
 Joe D

[Joetrain59]

I'm now battling the flu:(  Anyway I have 2 pix of the PCB. Very confusing to me, as to what traces to cut, and if I cut even get in there to try and cut. Very busy board!





 Any help gratefully appreciated.
 Joe D

[mmagliaro]

Ouch...
Well, first,
The 4 black wires that go more or less to the 4 corners of the board, are those two pairs that go to the wipers on
the trucks?

And does the blue/red pair go to the motor?

And finally, that red/black pair coming off the left side of the board... does that go over to the cab/LED board?

May as well start there...

If all that's right, and since you've blown the decoder already anyway, you may be able to just jumper from the one of the black truck pairs to the red/blue motor wires to get the motor running.   Not sure about this yet.  Let me think.  I don't think you could hurt anything if the decoder is already shot.

I'm a little worried about the coreless motor in that thing.  If it's not a 12v motor, this is going to get complicated.

[Joetrain59]

Max, you got the wiring right. The loco does run hood forward, but not cab end reverse.. Really have no need for decoder, but want to keep lights.
 Thanks. Checked Marks review, it is a can motor.
 Joe D