How to add DCC and sound to the three truck shay.

[bobgrosh]

OK, Thanks TOC

So those have no voltage on them, just go to dry contacts. Great! I assume it creates six interuptions per revolution of the drive shaft?

Now, what is the "two terminal screw connector", J3 for?
Terminal J3-6 has a white wire in it , J3-5 has nothing in it. There is no indication as to what this does on either drawing. It is shown the same on both drawings and matches the loco. It looks like an "option jumper", move the white wire from  6 to 5 to accomplish something. But what?

[bobgrosh]

I connected an ohm meter to the two blue wires. I disconnected the drive shaft from the front truck so I could rotate the drive chain.

Obviously, the blue wires are not chuff triggers, because they only close three times per revolution. Chuff contacts would close 6 times per revolution. They may have someting to go with determining the speed of the loco with some cards but are totally useless for generating a chuff.

[Curmudgeon]

Good Lord, Bob.
"Obviously, the blue wires are not chuff triggers, because they only close three times per revolution. Chuff contacts would close 6 times per revolution. "

If they close when you turn the shaft, they are EXACTLY chuff contacts!
ALL Bachmann Shays, since day one, serial number one, have exactly three (maximum) chuff per revolution.
That said, some folks decided to put a different set of contacts on the drive to get 6 per.
BIG problem is NOBODY runs at prototypical speed. At the speed everyone runs these, you might as well have a noise-maker out of an Anniversary with the contacts tied together.
All you'll hear is a roar.
Make your own or live with it.
Those ARE the chuff contacts!

[Tony Walsham]

At least the chuff contacts work in the Shays.

They don't at all in the Climax and not very well in the Heisler.

[bobgrosh]

Earlier I said:

... Now, what is the "two terminal screw connector", J3 for?
Terminal J3-6 has a white wire in it , J3-5 has nothing in it. There is no indication as to what this does on either drawing. It is shown the same on both drawings and matches the loco. It looks like an "option jumper", move the white wire from  6 to 5 to accomplish something. But what?

Upon further investigation, I found that removing the white wire from J3-6 will remove the power from the smoke generator WITHOUT REMOVING POWER FROM THE CAB LIGHT!

Also, connecting the white wire to a decoder function output allows independent control of the smoke via a button on the handheld. The brown wire will control the cab light and the white wire will control the smoke. (Side note: I set a qualifier for the white wire function so it only comes on when the loco is moving so the generator will not run dry while sitting on a siding should I forget to turn it off via the front switch. This really means I no longer have to bother with the smokebox door at all. Just leave the switch on and forget it.)

Great job Bachmann, but why is this handy feature a secret?
Now, what does the screw terminal next to it (J3-5) do?

[Curmudgeon]

You're just doing this the hard way, Bob.
You go through all of this, and one of them surface-mount components will fry and you'll be up at 0230 trying to draw a schematic.

We just rip the boards out.
I use Sierra for flicker driver, pitch the smoke (just imagine billing your time hourly to a custopmer trying to get the smoke to work), and add what we want, and never have to worry about secret jumpers.

On the three-truck, I mount Sierra, throttle, trigger board all in the fuel bunker, batteries and speaker in water bunker, and just pitch the rest.

[bobgrosh]

Probably right.
Read my smoke post.
So I need 12 volts for the smoke.
and a resistor will do for the cab light.
So, the regulator is not needed.
Don't know what all those big capacitors are for, but without a regulator, well, they are potential land fill. I assume that when I disconnect the wires and plug to install the Tsunami, all that stuff is disconnected completely. (got to check that)

Diodes, What are all those for? Two would do for the directional lights. Four of them were to supply DC constant polarity the regulator. So, they are potential land fill.


The board stays, it has all those wires from the trucks and the plug to the tender. And besides, IT HAS SCREW TERMINALS for the track and motor. but, if they did this board like Aristo, it will be nude when I'm done with it.