Mixing Transformers

I would recommend getting a whistle button and adding that rather than mixing transformers, Lionel part 6-5906. This way you will avoid electrical problems that may occur as the two transformers might not be in sync with each other and short out one of them when trying to use the whistle feature. Without knowing more about your transformers I highly recommend staying away from what is called phasing.

BTW; Lionel's 022 post war switches are 031 sized curves.

Lee F.

I know that Lionel has separate sail push buttons that activate the horn, bell features for transformers that do not have them.  The are wired between your transformers and the track.

"Can I additionally connect  the small Lionel transformer  to the track for whistle use only, if I am careful to only engage that function?"

No.

Thanks for the replies.

 I'll look for the Lionel whistle button. How does it work?? I found a button mechanism in the box which contained the small Lionel transformer that I mentioned above. This thing had a holder for a 'D' battery, which I presumed would provide the DC for the whistle. Looked so rinky dink that I never tried it, plus the battery holder was severly corroded. Is this the same as the Lionel part mentioned?

runtime

No, that was a late postwar cheap alternative to including a whistle controller with a DC rectifier. The 6-5906 was introduced with the advent of Railsounds; it allowed the addition of the bell sound.  One could be added to a transformer with a built-in whistle controller, or two could be used with a transformer with no whistle function, to have bell and whistle both.

I primarily run 'conventional', ie - pre and postwar engines where the steam tenders have whistles and the diesels have battery powered horns. I  do have a few later diesel engines which I believe are from the MPC era; I never have investigated if they have any horn capabilities.

The batter powered horn/whistle controller is simply a battery holder with a momentary switch and two termials for wire attachment. The Lionel instruction sheet shows the switch connectedin series:one terminal to the track lockon (left side - which seems to be center rail), and the other to the transformer ( I'm not using the outfit's 1073 for track power, so I don't know where in the track power circuit it needs to be, or if it matters). I tried this today, but only seemed to produce a short circuit.

1If I get aa 6-5906, will it work with a simple transformer, and why would I need a second one??

Thanks,

runtime

ps - This outfit was given to me, and includes, in addition to the above, some 027 track, a Prairie Steamer and tender in need of repairs, and some freights, none of which are listed in the colors I have in any print or on line guide I have seen. So much for free gifts.

The second 6-5906 is only necessary if you need a "bell" button. You can use just one with the transformer if all you need is the whistle. I have a couple of Prewar engines and their whistles do not perform as well when activating them with this button, compared to  using the whistle control built into a ZW. The diode in the 6-5906 seems to drop the track voltage somewhat when it is activated, leaving you less to operate the whistle--whereas a postwar transformer actually increases the track voltage when the whistle control is activated.  I do prefer to run at lower speeds; at higher speeds the problem may not be as pronounced.  Or you could look for an old 167 whistle controller instead. IIRC, that had a resistor in it that was in series with the track during operation; when the whistle was blown, the resistor was switched out as the rectifier was switched into the circuit, meaning that the track voltage was relatively unchanged.

If your MPC diesels have horns, they should operate with either the 6-5906 or the 167, or a postwar transformer with whistle control.

Hope that helps...

Thanks nickaix, that is quite helpful.

I will see what my LHS has, or contact Olsen's for one or the other controller. I don't know what IIRC means, but I assume it refers to the operation of the 167.

runtime

The 167 (and the 66 before it) used inductors, not resistors, to drop the voltage when the whistle was not in use.  The 6-5906 does the job more simply with silicon rectifiers, which were not available earlier.  It has the disadvantage of dropping the voltage when the whistle is in use.

However, you can easily build your own version of the 6-5906 with the more desirable behavior, from a handful of rectifiers and a couple of pushbutton switches.  You would need about a dozen of these:  http://www.radioshack.com/product/index.jsp?productId=2062591 .  It would also be able to generate both bell and whistle commands from the same unit.

("IIRC" = "If I remember correctly.")

Hello Bob, Thanks for the info.

I inquired at my LHS about a 'Lionel Whistle control' and  was told Lionel no longer makes any, and that they were ' very flimsy' anyway.

So home built is fine with me. Can you tell me how to wire up this 'dozen or so' rectifier diodes and the momentary switch, and how to place them in the track power circuit?

Thanks as always,

runtime

Make a complete loop of diodes, about 12 of them but certainly an even number.  Within the loop, connect the cathode of one diode (the end with a ring around it) to the anode (the other end) of the next diode.

Pick two points in the loop exactly opposite each other, so that there are two strings of 6 diodes each between the two points.  Connect one of these points to the center rail and the other point to the transformer terminal that was connected to the center rail.

In each string, connect a normally-open single-pole-single-throw (SPST) pushbutton or momentary switch around all but one of the 6 diodes in the string.  One of these will be the whistle button, the other the bell button.

If you prefer, you can use a single momentary single-pole-double-throw (SPDT) switch instead of the two pushbuttons or SPST switches.  Connect the switch's center terminal to one of the two points in the loop.  Connect each of the switch's other terminals 5 diodes away in one of the 6-diode strings.  In one direction the switch will blow the whistle, in the other, ring the bell.

Thank you Bob.

As I understand your instructions:

I'm OK with paragraphs 1 and 2.

1. How do I "connect...(a switch)..'around' all but one...of the diodes"?

2. Which half of the circle is 'Whistle', which is 'Bell'?

I currently have no 'Bell' capable engines, since I run all Postwar plus a few MPC engines which I don't think have any sounds; But I may still wire for it for the future.

BTW - Do I need a similar setup to operate a postwar uncoupling track? I have one in my layout (should add several more) but I never wired it up yet.4

Many thanks,

runtime

1.  Connect one of the switch's terminals to one end of a string.  Connect the switch's other terminal 5 diodes away, 1 diode from the other end of the string.

2.  The string with the cathodes closer to the center rail does the whistle.  But you can label the pushbuttons either way.  Then, if it works backwards, just swap the entire circuit end for end.  Actually, your postwar whistles will blow with either pushbutton--only a modern locomotive will distinguish between whistle and bell.  So you could leave one pushbutton off; but you still need all the diodes, so that's not much of a saving.

Uncoupling tracks are very different from whistles.  See whether you can find yours among these:  http://pictures.olsenstoy.com/searchcd2h.htm

Hello Bob,

Thanks for the 'how-to'.  Neither of the two Readio Shack stores closest to me carry those diodes, so I will order them on-line. I did pick up a momentary switch.

I'm thinking that this bunch of diodes is going to take up a bit of space. I may be able to string them along the inside walls of a wooden block-switching box, but need to determine how to attach them to the wooden walls without creating any shorts. Are there some kind of standard mounting materials for building up circuits, some kind of perforated boards perhaps? or clamps or something else?

My block -switching panel is 3 " W x 2 " H x 24 " long, containing 11 std size toggle switches; so there is limited spacxe to work inside.

Appreciative as always,

runtime

I would think about using something like this:  http://www.radioshack.com/product/index.jsp?productId=2102862

You can mount the diodes vertically, with one lead through the board, the other in the air.  By alternating direction from one diode to the next, you can get the chain that you need by soldering the leads of adjacent diodes together under the board and above the tops of the diodes.  You can make a compact 3 x 4 diode array like this:

A---C   A---C
|   |   |   |
C   A---C   A
|           |
A---C---A---C

"A" and "C" denote which end of the diode is up.

lionel post war transformers with built in whistles had a 5 volt compensating winding that was cut in as you hit the button. this was to make up for the 2-3v drop across the rectifier disc. the new add on buttons are junk. they use a 1-2 amp diode compared to the 5-8 amp discs. that was because of all the cheap can motors used in the set locos and in the new air whistle tenders re-introduced in the 90's. and now with all electronic boards the current draw is even less. as you press the button, (a spdt sw) all the track power flows thru the tiny diode. as for the battery add on, the idea was to superinpose a DC signal on the AC power for the DC whistle/horn relay to pick up. but after a few times the battery was cooking itself from overheating from the AC. just get your self a good post war transformer with the whistle and go from there.  or find a good #167 postwar whistle button to use like the new cheap add on ones.

oh,and stay away from the CW transformer used in the new sets. they are burning up the circuit boards inside left and right. the store i do repairs for has over 20 right now to set back to Lionel for warranty replacement. and definitly don't try to run big postwar locos with them!!!

The diodes in the 6-5906 (and the ones that I recommended) are rated at 6 amperes, not "1-2".  The switch in the 6-5906 is a normally-closed SPST, not SPDT.  The switches that I recommended are normally open, so that the voltage is raised when the whistle is blown.

Hello Bob,

I picked up the diodes, a board, and a push button switch at Radio Shack. I will sketch the circuit on paper before soldering, and I will try to scan it and post it to this thread.

runtime

Good idea.

Well Bob, I think I finally managed to get my Whistle Control Diagram scanned, uploaded, copied and downloaded to this thread.

Please let me know if this correctly follows your instructions, and will make the whistle/ horn blow:

Thanks,

runtime

That looks correct, except that I think you have swapped the labels, "Track Center Rail" and "Transformer Variable Output".

lionelsoni

That looks correct, except that I think you have swapped the labels, "Track Center Rail" and "Transformer Variable Output".

Not at all Bob. I was assuming that the whole whistle thing was in parallel to my existing track power. Reversing the labels would have ALL power to the tracks flowing through the diode circuits.

Should it be the former or the latter?

Thanks,

runtime

The track powered through this gadget is going to be a couple of volts lower than the transformer voltage.  So, if you run to one of those blocks that bypasses it, you will see a jump in speed.  I do recommend connecting the transformer on the left and powering everything through the new circuit.  That will also make the DC component of the whistle signal positive, which will agree with any modern whistles that you might put on the track.

Hi Bob,

Thanks for continuing to monitor this thread.

I will of course accept your recommendation, as my knowledge of electronics is close to nil.

I just read up on diodes and rectifiers on Wikipedia, to try to understand how this device will work. but I still don't quite understand what will happen to the transformer output when run through this circuit.

I understand that diodes act like a one way valve, lobing of half of the sine wave of the AC; I'm not clear how the two strings, facing in opposite directions function. How do I still get AC to the track? I also don't understand what happens when I close the switch, bypassing all but one of the diodes.

If I were to take a guess, using the sine wave concept, I would say that one string passes through a bunch of tops, while the other passes the bottoms, which will somehow reassemble atthe output end to look like the original AC. Then closing the switch will send along just some tops, ie lumpy DC. Am I close?

BTW will this device generate much heat?

Appreciate your patience with me,

runtime

The trick is that, while "ideal" diodes would act like simple check valves, the real diodes that you used have a small imperfection that we can exploit.  When they are what we call "forward biased", that is, when the "valve" is open and passing current, it has a small voltage drop across it, about .65 volts.  So the string of diodes reduces the amplitude of the half cycle that gets to the track by an amount that depends on how many diodes are in the string.

Before you push the button, there are 6 diodes in each string; so both the positive and negative half-cycles are reduced by the same amount, about 3.9 volts.  When you do push the button, the positive half-cycles are no longer reduced by this amount, but by the forward drop of only one diode, or about .65 volts.  The fact that the positive half-cycles are larger than the negative ones means that the average of the reassembled waveform is no longer zero, but a few volts positive.  This is the DC component that the whistle relay in the train responds to.

It does generate heat, but only a few watts per diode.

I think I get it.

I'll let you know how things turn out.

runtime