Wiring Diagram for a USRA Mikado 2-8-2 Sound value equipped

[park_ridge_dave]

Hi,

New on forum. I have a Mikado 2-8-2 locomotive that is shorting out my DCC system. If I disconnect the tender (where decoder lives) it makes all the right noises (whistle bell steam etc.) but obviously no motor to make it run. When I hook it up to the locomotive I get shorted main power at about 3 amps.

I have opened the shell and no wires look pinched etc.

Does anyone know where I could get a schematic/wiring diagram for this unit?

Also, any thoughts about what could be causing this? 

Thanks, Dave

[Len]

Unless you can find one someone made on their own somewhere on-line, there are no "official" wiring diagrams of Bachmann locos. Unfortunately.

Len

[park_ridge_dave]

Kinda what I expected... Sigh  Guess I'll get busy and draw one up. Thanks for confirming that though.

Dave

[Tenwheeler01]

Just to get a clear picture of your issue.  Starting with DCC track power is off,  place Locomotive plugged into the tender on the rails, turn power on to the track you get a short?

Also is this a USRA 2-8-2 SoundValue loco?     

[park_ridge_dave]

Yes it is a sound value locomotive. I found two problems:
1.) I had a nut loose on the tender ( me). I didn't look at the assembly drawing very carefully and managed to get the trucks reversed. This caused the rails to be opposite the wiring (right and left rails) on the locomotive. Short sends the DCC into current limit reset. Reversed trucks as per diagram Short fixed.

2.) Inspection of PCB board on tender revealed suspicious looking solder joint on motor+ lead reflowed joint with soldering iron Locomotive now runs again.

3.) Found a suspicious joint on Decoder Re-fluxed and reflowed solder with heat gun (SMD). Just in case.

More questions:

1,) Does anyone have a mfg. part number (e.g. Molex etc.) for the connectors that are used on the PCBs? It is much easier to order them if I don't have to spend 2 days figuring out the part numbers ( sigh lol). I figure that I will just make new wiring harnesses for the replacement board (see below).

I have spent several hours sketching up wiring diagrams and doing circuit traces for this loco/decoder installation.

If I get time in the not too distant future, I will redraw them in some suitable format and make them available.

I have ordered a Soundtraxx 884814 TSU-BH2 Tsunami 2, Steam-2, 8-Function, (2 Amp) Digital Sound Decoder HO Scale. I spent so much time to this point that I will just go ahead and design an installation harness for the unit with separate (front and rear) headlights, maybe smoke unit, and Firebox light.

That'll keep me off the streets for a few days! I went and ordered 25ft of AWG #30 extra flex black wire so I NOW HAVE TO DO SOMETHING!
And yes I am retired so I have loads of time.

Thanks to all who checked in,
Dave

[park_ridge_dave]

1,) Does anyone have a mfg. part number (e.g. Molex etc.) for the connectors that are used on the PCBs? It is much easier to order them if I don't have to spend 2 days figuring out the part numbers ( sigh lol). I figure that I will just make new wiring harnesses for the replacement board (see below).


I have ordered a Soundtraxx 884814 TSU-BH2 Tsunami 2, Steam-2, 8-Function, (2 Amp) Digital Sound Decoder HO Scale. I spent so much time to this point that I will just go ahead and design an installation harness for the unit with separate (front and rear) headlights, maybe smoke unit, and Firebox light.

OK Thanks to Norman C. at Soundtraxx: the 12 pin cable connectors are a JST SR 1.00 mm. THANK YOU NORMAN!!
The 8 Pin connector for the tender to the locomotive is a Molex 510210800 (Thanks to self ).
I will layout and build the connectors/cables to implement firebox lighting, and separate front/rear headlights.
Do you guys think smoke is worth it? if so, suggestions on a unit?
If anyone is interested I could post pics wiring diagrams?

OBTW it took 4 days to track down all the info. LOL

Cheers, Dave

[trainman203]

Smoke units are never worth it. They are for toys, not Model Railroads.

The smoke never looks realistic, looks like a cigarette instead of a train engine. The physics of prototype steam locomotive exhaust cannot be scaled down to Model Railroad size.

 Plus, the smoke settles on everything in the room in a greasy film. 

Firebox flicker is a much more worthwhile pursuit.  An installation that would realistically glow in the cab.  Anyone who has ever seen a hot steam engine at night knows what I mean.  Especially an oil burner.

[Terry Toenges]

"...on everything in a room in a greasy film." Including your lungs? I never really thought about that part of it.

[trainman203]

Could be.  I never thought of that either.

[Tenwheeler01]

And the smell.

Also there is a big difference in the standard available you install smoke units and the ones BLI and MTH use.  There smokes require costume decoders that have the components and wiring to run them.  BLI's have 8 CV for controlling there smoke units.

So installing one is not worth it.   And BLI and MTH ones are cool to play with but. 90% of the time I do not run them.   The one I like the most is the one in the MTH SP Cab forward. The fan blows a constant column of smoke at Idle and it gets quit heavy under load. My next fav is the Blue Goose.

I only have a handful of BLI/MTH locos.  Most of my roster is Bachmann steam locos.

The empty space in the smoke box of the USRA 2-8-2 is great place to add weight. The added weight gave my 2 extra pulling power and it tracks though turnouts better now.   The USRA 4-6-2 has a factor weight in the smoke box. The 4-6-2 weight fits the 2-8-2 but I cannot find it as a part on the parts site. And I am not sure way it is not in the 2-8-2s.