Kato Big Boy with Factory Sound Wired Wrong

[gkoproske]

I waited for the Kato Big Boy with factory sound.  My first one tracked poorly.  Pilot truck and first driver set derailed within 3 feet.  Running on analog, it ran backwards.

Exchanged it with my vendor.  Ran it on the MVNS T-TRAK layout at the Springfield IL show, DCC.  Ran well.  Got it home, and ran it analog.  It ran backwards.

Vendor indicates 1 out of 4 have wiring issues.  That means mine account for 2 out of 8.  Vendor says I should pull the tender and switch the wires for + and -.  Just now looked at videos and Spookshow to see how the tender detaches and its shell comes off.  I've been in the hobby long enough to realize a user fix is more expeditious than a manufacturer fix.  And I understand the factory sound probably was not installed in Japan.

[C855B]

Gosh, Glenn. You told me on Sunday you login here only when you have problems... and here you are! 

Sorry about your Big Boy. That sucks. But once you get it straightened out, it'll run a damnsight better than my two Athearns. They've been on the bench for years waiting for the roundtuit to replace traction tires some "helper" in the club stretched out trying to rerail them at two Belleville shows. If it wasn't for my Kato FEFs and a B'mann J I wouldn't be running steam at all.

[k27463]

I'm sure they wired it up and -then- checked direction polarity -- when it was wrong, they simply set the CVs to change direction; but that doesn't fix it on DC.

I'd be hesitant to run such a large locomotive with multiple pickup points on DC anyway; any derailment could run the full amperage of a DC transformer through the decoder.

[peteski]

I'd be hesitant to run such a large locomotive with multiple pickup points on DC anyway; any derailment could run the full amperage of a DC transformer through the decoder.

That's not how it works.  This is a DC loco with the decoder added between the motor and the rail pickups.  The rail pickups are identical to how they are in DC version.  If the model derails in DC (with our without the decoder) the amperage will be passed through the pickups only. Decoder is not involved passing the current during shorts.  What could damage the decoder is either excessive voltage or possible voltage spike.

[k27463]

That's not how it works.  This is a DC loco with the decoder added between the motor and the rail pickups.  The rail pickups are identical to how they are in CD version.  If the model derails in DC (with our without the decoder) the amperage will be passed through the pickups only. Decoder is not involved passing the current during shorts.  What could damage the decoder is either excessive voltage or possible voltage spike.

Whoops, sorry, you're right.

[gkoproske]

All this poured out of the Big Boy tender.  Norman told me to find the red and black wires running to the tender wheel pickups and switch those.  They are hidden behind two side plates which have to be detached. [ Guests cannot view attachments ]

[peteski]

 

[C855B]

That's certainly a nightmare. Sometimes you really don't want to know what's in the sausage. 

[ntex]

Definitely not the work of the previous Kobo installer!

[learmoia]

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[Dwight in Toronto]

Definitely not the work of the previous Kobo installer!

No kidding!  I’m pretty sure that ‘previous Kobo installer’ will be appalled if/when he catches up with this thread.  What a shame.

[learmoia]

I'm still trying to wrap my head around why Kato didn't design the locomotive around the idea of motor and light Decoder in the boiler and sound only decoder and speaker in the tender.

[peteski]

I'm still trying to wrap my head around why Kato didn't design the locomotive around the idea of motor and light Decoder in the boiler and sound only decoder and speaker in the tender.

Simple:  they wanted to produce a unique dual-motor articulated model never done in N scale.  With separate engines each with its own motor with a large flywheel there simply isn't room for a sound decoder.  Ignore the space behind the front engine - I removed its motor before taking the photo. With the motor installed there is no room between the back of the front engine and the chassis.

You could stuff a non-sound decoder right in front of the backhead, but no room for a sound decoder.  Plus for maximizing the weight of the loco (in conventional models) it makes sense to keep the loco as full of metal chassis as possible and put the lightweight decoder in a non-powered tender.

[Jbub]

I think Ian was trying to ask why Kato doesn't just put a normal motor and and function decoder in the engine, which you say can be done, and then add a sound ONLY decoder in the tender for sound units.
I'm sure it could be done that way but one thing I think may be difficult to overcome would be syncing the chuffs to at least one set of drivers. It would be impossible to sync it to both without the use of mechanical system to send a pulse from each driver set to the decoder, but to have it even be remotely close without having a BEMF readback to the decoder from the motor might ruin the effect for those who are interested in sound.

[learmoia]

I think Ian was trying to ask why Kato doesn't just put a normal motor and and function decoder in the engine, which you say can be done, and then add a sound ONLY decoder in the tender for sound units.

Right...

The dual motor design is innovative but if your in the market for a DCC/Sound Big Boy.. the Broadway Limited or Athearn examples look very tempting in comparison.

You'd have to work with a DCC mfg to design a custom decoder, but what if you did a small chip like the LL SW1200 right under each motor..

I wonder if the locomotive is designed with the Japanese market in mind where DCC Ready may not be as important.