Per @gunrunnerjohn's suggestion, I decided to take on building my own whistle box.
I use a KW transformer with the original rectifier disc. I also have mostly PS1 stuff from MTH. As I started commissioning my fleet, I was not able to consistently blow the horn on all locos, and on the ones I *could* get the horn to blow with the KW, the voltage would **** near drop out and the engines would stall as the horn blew. I did try using some lighted cars to put a load on the transformer, but it really didn't do much.
Also, as many of you know (but I didn't), with the rectifier disc you get *either* the bell *or* the whistle, but you can't have both. The polarity of the track connection determined which one was going to sound when you wiggle the KW's horn handle *just so*.
But the biggest issue for me was that I couldn't consistently use the KW to program my PS1 boards (or, to be more precise, return them all to factory settings using reset 18). That was an issue, because the smattering of boards that I had would have various features turned off or on and it made doing things like uncoupling a bit tedious.
So, after researching the issue, and with some of John's advice, I cobbled together about 12 bucks worth of parts from the local electrical surplus store and got busy. (I originally planned to do it next week while I watched basketball, but we all know how that ended up >
Took me about 2 hours altogether, using some really crude soldering, some electrical tape and frequent visits back to John's pictures from his other thread about building a box. And wouldn't you know it, this non-electrician mechanical guy was able to get it to work on the FIRST TRY!
I did do a couple things slightly different than John's. First, I used six diodes instead of 5 in each direction. Just basic, run-of-the-mill 400V 6A diodes. I did run some tests with 5 diodes each direction vs. 6, but sometimes with 5 the horn would just blow randomly for several seconds. Interesting, but not the effect I Was looking for.
Second, I used Normally Open switches instead of Normally closed. So instead of running constant voltage and then slightly dropping the voltage across the diodes by opening the circuit when the switch is pressed (resulting in a corresponding slowdown of the loco when the horn blows), the voltage is slightly boosted when the horn switch is closed (biasing the DC positive instead of negative I guess). This was a bit more desirable to me, since I tend to run things pretty slow anyway, and the very slight speed boost isn't enough to bother me. There's a video posted so you can see what I mean.
All in all, Im super excited that I'm learning some new tricks with the help of this forum. Next up: Gonna make me a bunch of BCR's!
Photos and video of the box in action!
Had to wrap the diode series in a bunch of tape to prevent accidental shorts . It's a mess, but I'm not a pro and I'm actually kind of proud. Too bad you can't see my bang-up soldering job! (It's bad).
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