Under The Hood: Wiring A Scout Tender For Sound

nice Mitch. I have a Prewar whistle in my 221 tender. 

Dave, That’s a 2222111 tender!  You forget, you stretched it.  LOL

I would sat part of the problem is there needs to be a air intake vent above the whistle intake. The shell looks too close to the mechanism and not enough air. Also the Bachmann motor is designed to run at 12 volts, and the circuit board output is about 5 volts. You would have to use a Lionel air whistle motor or smoke unit motor.

You will also get more sound by by-passing the resistor on the circuit board.

Doc I was wondering what to number it 

Skip Tyco, they are voltage hogs too.

You know I saw a bunch of variable 3v min in to 3-35v regulated booster boards good for 2a-4amp draw.  5-2a boards for $12 & change.

Mitch, I admire your creativity and your willingness to explore modifications, and hopefully improvements!

I have one of those Bachmann HO whistle sound mechanisms. I never found it quite as loud or as pleasing as the whistle sound units from the Lionel tenders... even the modern era starter set tenders. I took one of those whistle units out of a tender and placed it under a postwar SP type caboose shell, which serves as a yard office. So on a small layout, I have a whistle sound for any small steam engine, even those with the Lionel slope style tender, which doesn't have enough room for that whistle assembly.

I also have one of the MRC push sound units, which I wired larger boom box speakers into, so now I get a much louder sound out of it, and get some slightly more realistic horn and whistle sounds, should I so chose.

My one Scout loco project was to re-wire pick-ups to the tender. Those Scouts have a tendency to trip into reverse when ever they hit uneven track, such as a switch or uncoupling track. I noticed the engine would make a "clunk" sort of sound when going over these because the slide pickups are so low.

So I removed the slide pickup from the locomotive, put new trucks with center rail pickups on the tender, and wired them together with a disconnect between the engine and tender. Presto, unwanted reverse problem gone.

I always advise folks wanting to experiment with rebuilding, making modifications or repainting, to begin with something cheap, inexpensive and/or very common. That way, no real loss if you mess up. And it is always a learning adventure that will often give you the success and confidence to tackle more complicated projects.

Nice post, Mitch.

Chuck Sartor posted:

I would sat part of the problem is there needs to be a air intake vent above the whistle intake. The shell looks too close to the mechanism and not enough air. Also the Bachmann motor is designed to run at 12 volts, and the circuit board output is about 5 volts. You would have to use a Lionel air whistle motor or smoke unit motor.

H'm.  Or a old horn/whistle relay and a rectifier, maybe?  

You will also get more sound by by-passing the resistor on the circuit board.

I know that was an issue on some of the older boards, but I thought that was addressed on newer ones?  

brianel_k-lineguy posted:

Mitch, I admire your creativity and your willingness to explore modifications, and hopefully improvements!

(clever Scout loco and other mods snipped) 

I always advise folks wanting to experiment with rebuilding, making modifications or repainting, to begin with something cheap, inexpensive and/or very common. That way, no real loss if you mess up. And it is always a learning adventure that will often give you the success and confidence to tackle more complicated projects.

Nice post, Mitch.

Thankee!  You've given me some fresh ideas!   

Mitch 

Well, if you like the whistle mechanism inside the SP caboose body, I'll save you some trouble.

- I placed 4 small squares of self-adhesive foam on the bottom of the whistle unit, to allow sufficient air flow to make the whistle sound.

- After repainting the caboose shell to look like a yard office, I took two scraps of wood, painted them grey like concrete, and placed them under the steps on each end of the caboose to raise the height... again for air flow for the whistle unit. Since the whistle assembly is black, it's not all that noticeable.

- I used plastic from a milk container to make window glazing, but only for the visible front side of the caboose shell. I left the back and side windows clear, again for air flow to the whistle mechanism.

You can do your own experimenting, but as with your above tender project, the air whistles - with their pleasing nostalgic sound - still need sufficient air flow.

As it turned out, airflow isn't the problem; the motor just wants too much juice...

Here's the whistle with its factory wiring harness.  Works fine on 12 volts or so or higher. 

I broke out an old whistle relay and did a test fitting.  Doable, but not with those nuts and bolts holding the trucks in place. 

So, I took a page from Lionel's book, and used some eyelets from my sewing kit to rivet the trucks back in place.

You say you don't have a sewing kit?  Shame on you!   

Incidentally, these eyelets from Hobby Lobby are a close match to the original Scout rivets. 

Wired some leads to the whistle motor bridge rectifier...

Preliminary test:  IT'S ALIVE!!!

Repurposed an Erector bracket for mounting purposes. 

The blued screw  (slightly offset) blends in with the finish.  

Test with the relay mounted! 

Now to assemble and test...

Long story short:  The whistle works fine...as long as there's no engine involved.  The motor only works when the locomotive isn't pulling much juice.  For example, a bump and go trolley works OK...

...but that's a tad silly, even for me.  

Oh, well.  The concept works and the air flow seems to be fine with the coffin tender shell on, so it's just a matter of finding a whistle that'll work with the rig. 

Mitch  

Maybe move the BR, or add one, to just before the relay points and ad a big capacitor between them. Getting started it seems like it wants all the amps it can get. I think the voltage isnt far off whats needed for the impeller holding speed.

  Try setting the throttle for a big engine, but winding the whistle up alone, then setting the engine on the rails (carefully ) to see if there is enough holding power at that throttle to keep the whistle singing.  Then you'll know if adding starting capacitance for it will work. 

Okeh!  Held the loco in place, cranked it up on high with the drivers spinning and the whistle sounded over a range of voltages.  So, your capacitance idea is sound!  Now:  a) What size capacitor should I use?  b) Where exactly in the circuit does it go?  

Thanks!

Mitch 

Well, the loco should be under load so it's drawing hard.

  You have to rate the cap voltage over anything expected, including spikes at blocks, etc..... 35v aught to keep it from popping; 50v safer yet. Bigger uf is better, but you can stack a bank of them if you wanted. Ac still goes to the relay's coil. Ac goes to the rectifier first, cap on the dc side, + to +; - to -, dc- to whistle, dc+ to the relay point A, relay point B to whistle motor+.

35v 1000µF cap across the DC outputs of the rectifier works like a charm!  Amusing side effect:  Since the relay is wired to feed AC to the rectifier, if the tender is placed on the track by its lonesome and the whistle is blown, the cap keeps the relay locked and the whistle keeps going.  Doesn't happen with a loco attached, but I'm gonna have to revisit the wiring just a eentsy bit.    

Mitch

Are those relay points isolated? Is it rectified and capped BEFORE it goes to the points? It has to be before the points to keep control instant. Otherwise you wait for the cap to run dry.

  If the points cant be isolated you need a second small 5-24vac relay triggered by the PW dc sensitive slug relay.

I barely got room for the cap.  I should put another relay in?    

A mean a small component sized relay, less than 1" square. Micro switches are bigger at times.