# Soundtraxx Sierra issue



## mdwildcat04 (Mar 11, 2013)

I managed to get my hands on a lightly used bachmann 2 truck shay, and an Soundtraxx Sierra shay sound card new in box. I plan to fit it with the Jr. Throttle, or maybe a airwire board. 

First problem, the manual indicates i need bulletin 6 and or 7 to wire this up with a dcc or rc system. I cannot find these online.

Second, the included 6 volt battery measures .06 volts. I assume its pretty dead. Is it necessary if I am running battery power for the engine itself. I assume the answer and how are in the above docs.


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## ewarhol (Mar 3, 2014)

I have bulletin 7 I can email to you off list if you want to send me a private message with you email address. Bulletin 7 goes over installing with DCC.

As far as the steam side of the Sierra sound unit and DCC I'm not sure. But I have a Sierra Diesel sound unit, it doesn't work well with DCC. The engine has an endless amount of notches, just keeps revving up forever after a certain point.


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## Pete Thornton (Jan 2, 2008)

> included 6 volt battery measures .06 volts. I assume its pretty dead


The lead cell battery they supplied is known to die after a short time. Lead acid batteries hate being left discharged.

I run mine with r/c and battery. There's a small voltage controller board kit they offered that allows you to use almost any battery voltage. I found one at Star Hobby in MD - call and ask if they have any more?

Do a google for "site:mylargescale.com soundtraxx sierra" and you'll get a bunch of threads full of useful knowledge.


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## Dan Pierce (Jan 2, 2008)

I have a lot of the old manuals also.
Tech bulletin 6 and 7 deal with dcc installs.
There are Aristo (pre revo), RCS and locolink manuals available also.
[email protected]


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## Dick413 (Jan 7, 2008)

if you go with airwire, in the instructions tells how to hook it up


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## mdwildcat04 (Mar 11, 2013)

Ok, so they show a linear voltage regulator, I assume knocking track/battery voltage down to ~6 volts. Would a switching regulator work? They can now be had for ~$1 and are more efficient.

On some setups, the motor wires are connected strait to the sound board, while others are going threw a optical isolator. My guess is linear vs PWM control of the motor? If I am using the chuff cam, do I even need to worry about that at all?


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## Greg Elmassian (Jan 3, 2008)

Yes, the PWM motor signal often looks like full speed all the time to the Sierra.. the chuff cam setting should really control that. You might ask TOC also.

Greg


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## Dan Pierce (Jan 2, 2008)

Sierra had a circuit board for the motor PWM feeding the sound board to eliminate the full speed syndrome.


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## mdwildcat04 (Mar 11, 2013)

so, this sound board was sealed in plastic bags, I assume it is brand new.

I built the voltage regulator part, and tested it. It put out 6.6 volts. When I hook the speaker and the voltage regulator, and power the regulator with a 9volt, it just rapidly clicks. The volt meter indicates the battery voltage is sagging too low. I power it with a 3 cell Li-po pack, it starts up, I hear the hiss, what I assume is the dynamo, and some other noises, but the green and red LEDs are rapidly blinking, the green one brighter then the red. WTF?


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## TonyWalsham (Jan 2, 2008)

Dan Pierce said:


> Sierra had a circuit board for the motor PWM feeding the sound board to eliminate the full speed syndrome.


The opto coupler is needed for steam locos with mechanical chuff timers. Without it the Sierra goes into a full run state and cannot drop back to idle for Fireman Fred and dynamo etc.

Before Sierra came out with their version I also had a similar item available.

I still have a couple in stock.
http://www.rcs-rc.com/content/1261/ssi-12v5/ 
Once sold out I will not be running them again.


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