Large Scale Central

What are these?

I purchased a Bachmann Heisler on eBay a while back and pulled it out of the box to do some mods on it today and noticed for the first time these things glued to the front of the rear truck. What are they?

Those look to me like reed switches for sensing magnets embedded in the track, possibly to trigger sound effects. Just a guess, however…

Here’s one I found on amazon [link]

[edited to fix typo and to add link and image]

Yep, traditional setup is bell one side, whistle the other. LGB makes magnets that snap into the track near one rail or the other, you then have sound system triggering at fixed points.

Greg

Got it! So, I just took off the coal load in the back and this is what I see. I don’t see any speaker inside for sound.

Looks like old PH hobbies sound unit, may be an rc unit in there… need pix with wires out of the way.

Speaker is probably under the boiler.

Greg

Looks like Sierra Sound card with a Bachman I/O Card or similar ilk to me.

Michael

Sierra sound board for sure. The two screw terminals give it away, and the two buttons for “programming”. Not sure on the other board.

Speaker goes to pins 9 and 10. You appear to have wires there going somewhere.

Small speaker can be under all the boards, look at the bottom of the engine for many holes where the sound will come from.

Craig Townsend said:

Sierra sound board for sure. The two screw terminals give it away, and the two buttons for “programming”. Not sure on the other board.

It was the battery that told me it was Sierra. That’s a lead-acid (as used in home security systems 20 years ago) gel battery and is undoubtedly dead. It is supposed to charge as you run along and keep the sound going when you stop. If you google “sierra sound battery replacement” you should get some ideas.

Actually, if you try to charge the battery while running, it is almost an exercise in futility unless you continue to run at a fairly good clip. Sierra provides a jack to precharge the battery.

Be that as it may, at this point in time, you probably can’t get that battery to charge. I have been replacing them with supercaps. I use three 6-10 Farad caps in series to get up to the necessary voltage. I even added a relay so that the system cuts out before the supercaps discharge all the way so they don’t need to recharge from “0” each time the engine starts. Starting at “0” volts the sound system will make all kinds of “motorboating” noise until the voltage is high enough to sustain the system.

Timmy, I have the Sierra manuals if you need/want them, email me if you do.

Greg

Greg Elmassian said:

Timmy, I have the Sierra manuals if you need/want them, email me if you do.

Greg

Email sent. Thanks!

Pete Thornton said:

Craig Townsend said:

Sierra sound board for sure. The two screw terminals give it away, and the two buttons for “programming”. Not sure on the other board.

It was the battery that told me it was Sierra. That’s a lead-acid (as used in home security systems 20 years ago) gel battery and is undoubtedly dead. It is supposed to charge as you run along and keep the sound going when you stop. If you google “sierra sound battery replacement” you should get some ideas.

Doing a Google search for Sierra sound battery replacement returns many articles from years ago. So, I am not clear what I should get to replace the existing battery.

The local Batteries plus actually sells the same lead acid gel batteries that came with the Sierra boards. I replaced mine with NiMh batteries.

I am not clear what I should get to replace the existing battery.

Any chargeable battery with the same voltage rating will do if you are running track power. Or do without and the sound stops when you stop the track power.

However, most people use battery power for the loco, which can be used to feed the Sierra without a ‘keep alive’ battery. You do need an optical isolator which they used to supply. Greg probably knows where you can get a replacement.

Link below is for a like size battery as provided by Sierra Sound when board was new.

https://ubcalarmbatteries.com/6v-sealed-lead-acid-agm-battery/6v-0-5ah-sealed-lead-acid-battery-with-wire-lead-terminals

You’ll need to charge the battery with an ancillary charging device on occasion as the onboard charging circuit is nothing more than a regulated power output. Engine on/run time at sufficient voltage and current output won’t suffice IMO and a given or routine proper charge interval is required at the least.

Michael

Use these wired in series to replace the battery and never worry about the battery (including charging it) again. If you worry about the load, put a 1 ohm resistor in the series. I do this on my Sierras (without a resistor) and have never had a problem.

Depending on the volume setting, the sound will continue for about 30-45 seconds after the engine stops receiving power. The lights will continue a bit beyond this. This is enough to get some of the shutdown sequence of the sound system. 10F caps have also been used with success and prolong the shutdown sequence. In either case, ther will be a bit of initial “motorboating” when the power comes back on. It does no harm and lasts a whole lot shorter than when the lead acid battery runs down. Even so, there is a way around this using a small relay and associated small capacitor to uncouple the supercaps prior to their fully discharging so that some charge is retained and you don’t start from scratch when the power comes back on.

https://www.ebay.com/itm/3pcs-2-7V-6F-2-7V-ELNA-DZ-Farad-Super-Capacitor-10x30mm-For-Power/112096523616?hash=item1a19793560:g:EqIAAOSwaB5Xr-1D

Try these for higher voltages with super caps wired in series.

6 pieces for $4.11 and free shipping., less $$ in bulk!!

https://www.ebay.com/itm/6pc-2-7V-10F-Cylindrical-Ultra-Super-Farad-Capacitor-High-Power-Supercap-10x26mm/113702182907?hash=item1a792d9ffb:g:sr0AAOSwTHlcnvSd

Yeah, I would be a little concerned about two 2.7 volt supercaps in series, which gives you a 5.4 volt cap, so you would need 3 of them, which is what I assume Todd did, 3 in series give you 8.1 volts, which should give you plenty of margin, given the “charging circuit” from the Sierra. When “building up” multiple caps, realize that supercaps are VERY intolerant of over voltage.

I would also agree with the 1 ohm resistor, in case you have a sensitive short circuit detector in your setup. All good suggestions and better than the actual battery in my opinion too.

Greg