Lionel KW Whistle Control

Hi Mike,

Although I"m not a regular poster on this forum, I have learned a lot from the knowledgable train enthusiaststhat post here and have been in this hobby for many years. This issue was addressed in past posts and if you do a search for "zener diodes" you"ll be able to gain some very useful knowledge. My suggestion is to replace the original rectifier disc with a zener diode from Newarkelectronics.com. The zener diode works great with all postwar and modern tmcc and legacy steam and diesel whistles. The original rectifier disc does not work well with modern tmcc and legacy whistles and horns.The zener diode part number is 1N3311B. I replaced the original rectifier discs in two ZW's and a KW transformer and I'm very pleased with the results. If you need installation instructions, please let me know.  

Bill

Fixing the rectifier only gives you a whistle. Not useful if you run modern stuff and want a bell. You can just make an external bell/whistle controller and forget the rectifier in the KW,  described here

www.jcstudiosinc.com/BlogShowT...=412&categoryId=

can be automated described here,with a pic of the diodes used and mounted

www.jcstudiosinc.com/OGaugeAut...AndWhistleController

Dale H

Here's my whistle/bell control that will do both.  All you need is SPST-NO buttons for the controls, I just used stuff in the parts box and that's what I had available.

Based upon your description, I'd say you have dirty contacts.

The rectifier disk may also need replacing.

you need to buy yourself 2 of lionel 5906 whistle controls they work great.

Why have two boxes with tiny wires that you have to buy when you can make a much better one cheaper?

No, as they are dropping the voltage all the time in the diodes.  You have to have about three more volts than normal to get the same results due to the diode drops.

They do the same thing as the Lionel sound activation button.

Will anyone who has built their own sound activation button please suggest a part number for a pushbutton switch?  When I search Digikey & Mouser, I'm overwhelmed by the options.  Thanks, Chris

Here's some red ones: http://www.ebay.com/itm/Moment...;hash=item35c99dc183

Here's some green ones: http://www.ebay.com/itm/Moment...;hash=item51af141c3b

The ones I was finding on Mouser and Digikey were $5-6 each!

Thanks, John!

I agree that it is better to build your own external ones. The ones from Lionel use about 20 gauge wire. You can build them more robust than that.

As for how you wire the external box, you can have the diodes normally in circuit and take them out of the circuit when you push the button. For me, this always speeds up the trains as it appears to me that I am adding 3.5 volts or so back into the circuit. If I wire them so that the diodes are normally out of the circuit and I add them in when the button is pushed, it seems that I am removing 3.5 V or so and the trains slow down. I chose the slow the trains down approach as there are places on my layout that I don't want to speed up the trains.

I have also wondered about the external xener diode approach. These diodes seem to get high marks for not affecting train speed. I would love to see an external approach using these.

Denny

The Zener diodes are used in the transformer in conjunction with the boost winding in the PW transformer, they're not a real solution to this issue.

I'm guessing with a bit more work you could build a box that minimized the speed change while still imparting a DC offset to the track, I never spent much time trying to do that.

Switching them in is pretty easy, just wire the switch to the NC contacts instead of the NO contacts.  When you push the button, it'll insert the diodes into the line.  For the box I pictures above, that would involved moving one wire on each switch to the opposite side.  You'd still have the speed change, but it would tend to slow it down and not speed it up.