# question about an older Sierra sound system



## robertalan51 (Jan 1, 2011)

Hi, again......picked up an older Bmann 4-6-0 a while back and the guy said it had a SIERRA SOUND board installed in the tender but wasn't working properly. I finally decided to check it out to see if I could get this thing to work. Or maybe remove it and reinstall it in another tender. The board says.....SOUNDTRAXX (2) 2001/SIERRA STEAM/800109/VER 1.3/THROTTLE UP. It has a big 6v rechargable battery . Does all this mean anything to you guys? there are no numbers on any of the terminals. I tracked all the wires and found 2 that were tied up and not being used. The engine or tender doesn't have any reed switchs for the whistle and bell. Could these wires be the whistle and bell wires? The previous owner installed 3 toggle switchs on the bottom of the tender ,not sure what they are all for. He also added extra power cables to plug into a trailing railcar with powered trucks and also to the engine. I'm just hoping to end up with a nice simple useable sound system. So. if anyone is familar with one of these, please share any info that might be of some use to me. Thanks, Rob


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## Dick413 (Jan 7, 2008)

you need a good battery also did you try it? do search for instructions to see how its wired. 
Dick


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## Pete Thornton (Jan 2, 2008)

a SIERRA SOUND board installed in the tender 
Rob, 

I have one or two of them, bought secondhand from a pal. Soundtraxx used to have the manuals online, but they aren't visible on the website. They will talk to you, so email or phone and ask for the manuals. 

Another good source is the R/C throttle manufacturers - RCS in Oz used to have wiring diagrams showing how to couple their throttles to the Sierra board - and they showed all the connections. Tony may read this and offer some advice. 

I found the Sierra wiring diagram on my computer, (a scanned page now a PDF,) showing all the connections. You should have two rows of 8 screw-in electrical terminals, one at each side, numbered 1-8 and 9-16. Right? Send me a message with your email address and I will forward a copy. 

P.S. The big 6V battery is certainly kaput - it is a lead-acid gel-cel used in alarm systems. They expire if you don't keep them charged. Recycle it carefully. It was used to keep the sound going while the loco is stationary with track power off. It was recharged while the loco was powered.


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## robertalan51 (Jan 1, 2011)

Thanks for the info.......this board has no screw terminals and no numbers. just a long multi wire plug in terminal. As far as the old battery goes.... what should I use to replace the big 6v ?


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## Stan Cedarleaf (Jan 2, 2008)

Robert... I have the manuals in digital form... email me and I'll send you one.. [email protected]


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## toddalin (Jan 4, 2008)

If the system works, if can work with a dead battery once the voltage is high enough. I had replaced the batteries in the past but now just use three supercaps wired in series. Now I never need to charge or change the batteries.

There are usually two toggle switches. One is for off/on (DPST) that disconnects the battery and wheel pick-upsand the other raises or lowers the volume. Pins 7 and 8 are the input from the wheels. Pins 1, 2, and 3 are for the volume toggle (momentary SPDT, center off) with pin 2 being the common. Pins 9 and 10 go to the speaker. Other pins are for other effcts (e.g., lighting).


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## TonyWalsham (Jan 2, 2008)

I have never seen a Sierra sound card that did not have screw terminals. The terminal # was etched on the pcb.

You can find instructions for hooking up various sound systems to RCS on board ESC's including Sierra here: http://www.rcs-rc.com/pages/instructions
What you will not find are instructions on how to hook up Sierra for regular track powered use.


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## Dan Pierce (Jan 2, 2008)

I have the pdf files that I downloaded from Sierra years ago for the steam and diesel largescale sound units I own. 
I can send them to you if you give me your email address, or perhaps Greg can add them to his web site if Sierra is ok with it.


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## robertalan51 (Jan 1, 2011)

Thanks for all the ideas.......what are "SUPER CAPS"? And how are they used to replace rechargeable batteries?


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## toddalin (Jan 4, 2008)

Posted By robertalan51 on 02 Feb 2014 08:20 AM 
Thanks for all the ideas.......what are "SUPER CAPS"? And how are they used to replace rechargeable batteries? 

Wire three in series and simply replace the battery by putting the + end where the battery + was and the - where the battery - was. You can also remove the charging jack if you desire because you will never use it again. 


Supercaps on ebay


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## Dan Pierce (Jan 2, 2008)

Sorry, you can not just wire these in series without knowing the ratings or the voltage being used to charge the lead acid batteries. 
Super caps have voltage ratings from 2.3 volts to 5 volts. 

If the lead acid battery is 6.3 volts, then the charging circuit is 7 volts or more and the 3 2.3 volt supercaps are not enough and these will charge up to the max output of the charge circuit, very dangerous to electronics. Do it if you want 1 time real smoke. 

And when I do use the supercaps, I use a properly set regulator to get the correct voltage to the caps. For the Sierra 6.3 lead acid battery replacement I would use a 6 volt regulator, and a diode in the discharge path back to the source.


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## toddalin (Jan 4, 2008)

Posted By Dan Pierce on 03 Feb 2014 05:29 AM 
Sorry, you can not just wire these in series without knowing the ratings or the voltage being used to charge the lead acid batteries. 
Super caps have voltage ratings from 2.3 volts to 5 volts. 

If the lead acid battery is 6.3 volts, then the charging circuit is 7 volts or more and the 3 2.3 volt supercaps are not enough and these will charge up to the max output of the charge circuit, very dangerous to electronics. Do it if you want 1 time real smoke. 

And when I do use the supercaps, I use a properly set regulator to get the correct voltage to the caps. For the Sierra 6.3 lead acid battery replacement I would use a 6 volt regulator, and a diode in the discharge path back to the source. 

The link is to 2.7 volt supercaps (2.85 volt peak) so three take 8.1 volts (8.55 peak). The Sierra charges at a rate of about 7.3 volts. I have wired three Sierras using three supercaps and have provided these to others who have also used them with no ill effects.

When the cap is dead and the rails get to ~9 volts, it comes to life with a couple whoops then acts just like the battery. You can shut down the power and still get ~2.5 minutes of idle sound before it dies with a couple whoops. If you re-power >9 volts before it dies, it's just like the battery. If the train runs along at


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## Dan Pierce (Jan 2, 2008)

Many people read these forums and some do not look at the specs. 
Over time links can fail to work and the value of the capacitors above would not be available. 
So, I stated values of capacitors and reasons to be cautious. 
And this info can be used for other sound units for battery replacement.


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## toddalin (Jan 4, 2008)

Posted By Dan Pierce on 05 Feb 2014 04:30 AM 
And this info can be used for other sound units for battery replacement. 

At your own risk. The Sierra charging system (and maybe the old Phoenix) that use the 6 volt gel battery have a very "robust" charging system. When the cap is dead, it presents a momentary "near dead short" so the charging system has to contend with this for a moment. 
I've tried using various series resistors and resistor/diode schemes to ensure that the charging system sees less load, but with the Sierra they always turned out to be unnecessary and actually kept the system from working as well as without them.


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