Sound Activation

[srguy]

Are there any inexpensive alternatives to the Lionel 6-5906 sound activation button??  It appears that $30 is the going price for these things.

[cjmeyers]

You could try to build your own:

http://www.slsprr.net/features/SoundBlkProtect.htm

But the cost of parts and labor might come close to just buying one.

Regards,
CJ Meyers
Member TCA

 

 

[steinie]

I have built two of these, one for bell and one for whistle. You can use Radio Shack parts to make it. Diodes are 276-1661 and the switch, must be NC type, 275-1548. I did not make the protection part, so these are the only parts needed. You can use 4 diodes in series insted of the 6 called for, on modern trains. So the cost was about $3.50 for each. Not bad, I did not need a box, just put them under my control panel. No circuit board is needed. Just solder the diodes together and put the switch across the single diode and you are done.

[steinie]

Circuit is here

http://www.facebook.com/photo.php?pid=31179498&l=91dd7ef8ee&id=1529718675

 

[srguy]

That's great info ... Will it work on a Williams Truebalst??? My Lionel button died.  I've never done anything like this.  I located the parts on RS website ... are the diodes soldered end to end?? Would you have a scketch or photo??

[lionelsoni]

Check out this recent topic:

http://cs.trains.com/TRCCS/forums/p/185196/2027932.aspx#2027932

 

[steinie]

Here is another drawing

http://www.facebook.com/photo.php?fbid=1642695197142&set=a.1642514712630.2076722.1529718675&type=1&theater

 

[Boxcar Bill]

They are $13.00 here http://www.mttponline.com/#!

 

Bill

[srguy]

Well, I finally got around to putting together a "homemade" sound activation assembly per steinie's instructions. In theory it should work but it doesn't!! Using the specified parts from Radio Shack I assembled according to instructions however I did not use the pushbutton but touched the two wires together instead (should work as well). I tried both the bell and horn function wiring  and all I got was brighter lights in the engine cab. I used 5 rectifiers per steinie ..... any thoughts on what's happening???

[gunrunnerjohn]

How about a wiring diagram for what you have?  I built one of these, worked fine.  I used this circuit, and I also added an additional switch across all but one of the diodes on the other side.  This makes it a universal horn/bell switch, it'll do either.

 

[lionelsoni]

Here is a link to the original topic:  http://cs.trains.com/TRCCS/forums/p/185196/2030793.aspx#2030793

 

[gunrunnerjohn]

Here's a picture of mine with the two buttons.

 

 

[srguy]

I couldn't access those links ... I used the diagram from stienie's facebook link in this discussion however I only used 5 rectifiers not 7 ... could that be the problem?? I'll try to post a picture over the weekend.

[gunrunnerjohn]

I used 5 diodes for each leg, and my push buttons short out four of them.  Works fine for both PW and modern whistles and bells.

 

[srguy]

Got it working this morning!!!

[gunrunnerjohn]

What was the problem when it didn't work?

[srguy]

As a follow up to "problem solved" .... When I tested the horn and bell function the train was in neutral and both worked. Tonight I tried it while running and nothing but dimming lights. Bothe engines in question are Williams with True Blast II. Put a 1990s era Lionel with horn only and it worked OK. Did not try my PW steam yet. Any idea on what's happening??  BTW I ran the Williams fast with plenty of power. 

[srguy]

Do williams horn units operate differently than Lionel's??

[srguy]

I tested all engines with the following results:

Williams w/ true blast II - horn and bell both work in neutral but not when moving

Lionel RS3 90s era w/ horn - horn works fine both in neutral and while moving

PW 2055 - whistle does not work at all either in neutral or while moving ... the buzz of the e unit changes sound but that's it.  What's happening here?? Any thoughts.

[gunrunnerjohn]

My first step would be to try a different transformer.  It seems that the top suspect is the rectifier in the transformer, I've replaced many of those with a diode.

[srguy]

I was testing the diode assembly on a very basic transformer that came with an rtr set in the early 90s ... probably about 40W.  I also have a KW running 2 other loops which I haven't yet tested. I'm still perplexed as to why the lionel diesel horn works under all conditions and the Williams only works in neutral.  Could the power draw under way be affecting the horn/bell performance?? I'm using a total of 5 diodes and thought possibly adding 2 more might resolve the problem. 

[lionelsoni]

You need a total of at least 6 diodes to meet the Lionel specification of 1.1 volts to activate a whistle relay.  The DC voltage that a total of n diodes produce is approximately (n/2-1)*.65.  This is .975 volts for n=5, but 1.3 volts for n=6.  Another diode beyond that wouldn't hurt.

[srguy]

Would it hurt to trim the length of the metal pin on the diode ... it's already larger than I expected.

[gunrunnerjohn]

lionelsoni

You need a total of at least 6 diodes to meet the Lionel specification of 1.1 volts to activate a whistle relay.  The DC voltage that a total of n diodes produce is approximately (n/2-1)*.65.  This is .975 volts for n=5, but 1.3 volts for n=6.  Another diode beyond that wouldn't hurt.

How do you come up with 6 diodes?  The diode rectifies the boost winding's voltage, so one diode gets the job done in any PW transformer that I've opened up.

[lionelsoni]

Does everyone understand that we've been talking about two different designs.  What I will call the "normally open" or "NO" design has two series strings of about 6 diodes each with the strings wired in anti-parallel.  There are two normally-open pushbuttons, which each short out all but one doide in each string.  The NO design can generate both polarities of signal and boosts the overall voltage when either of the pushbuttons is pressed, speeding up the train.  It looses a couple of volts when not in use; so it has to be used with a transformer that has a little headroom above what is needed for the trains.  The NO design should have at least 10 diodes.

The NC design has one series string of about 5 diodes with a sixth diode wired in anti-paralled with the 5-diode string.  There is one normally-closed pushbutton which shorts out the entire circuit.  The NC design can generate only one polarity of signal and drops the overall voltage when the pushbutton is pressed, slowing down the train.  However, it does not lose any voltage when not in use.  The NC design should have at least 6 diodes.

 

[gunrunnerjohn]

Thanks for the clarification Bob, I didn't realize we were talking different designs. 

[srguy]

I'm a little lost with the technical explanation. I'm using NC push button, 5 diodes and a very basic 40W or so 90s era transformer .... do I simply add another diode or do I need to do something else???

[lionelsoni]

I just noticed that I missed John's question above.  He asked, "How do you come up with 6 diodes?  The diode rectifies the boost winding's voltage, so one diode gets the job done in any PW transformer that I've opened up."

The copper-oxide rectifier diode in a postwar transformer doesn't rectify just the 5-volt boost winding's voltage, but rather the total of the main winding and the extra 5 volts, but not for long.  The whistle control switches a low-value resistor around the diode to restore most, but not all, of the half of the waveform that the diode excluded.  The string of 5 (or more) diodes in the gadgets we're talking about do the same thing, but more reliably, since the resistor voltage varies with the load current and the diodes' voltage does not.  Not having enough diodes in the string restores too much of the waveform, not leaving enough DC voltage for the relay.  You could make one with a single diode and a resistor; but its performance would be more erratic than the multiple-diode version.

The big disadvantage of the NC scheme is that it drops the voltage generally, not having the 5-volt boost that was available in the postwar transformer.  The NO scheme gets around this by dropping the voltage all the time when the whistle isn't blowing.  Then it restores some of the lost voltage when the button is pressed.  Either design has one diode in anti-parallel with a string when the whistle is blown.  The difference in the numbers of diodes, that is however many in the string minus the one in anti-parallel, determines how much DC voltage is present.

Srguy, just add another diode or two to the series string.

[srguy]

Thanks Bob ... can you tell me why the Williams units horn/bell work in neutral but not while moving??

Jim

[lionelsoni]

No idea.  This is a pervasive problem when working with modern trains and transformers.  In olden times, it was possible to know what was in the locomotives, tenders, and transformers; so problems could be analyzed.  Now, the manufacturers are all holding onto their trade secrets.  All we have to go on are some broad principles and tidbits of information that can be gleaned by looking at signals.  So I could give you a guess about a Lionel whistle relay; but that's not what's in a Williams locomotive.

Have you tried adding the extra diodes to the string?