Unable to activate Williams True Blast Horns using old Lionel ZW transformer

Simple answer, the difference between a metal oxide rectifier disk and modern electronic controlled output.

@James Brown posted:

  Does the whistle just not send enough power out to activate?

Bingo.

Also, let's say you miswired your ZW to the track (U to center rail VS U to outer rail) then you would be applying opposite DC offset for bell. But you didn't say you got bell instead of whistle or horn- which makes this a less likely answer.

Again.  CW80- modern electronic manipulation of AC waveform for bell and horn/whistle function with a known DC offset regardless of load.

VS

ZW transformer using less efficient metal oxide disk style point contact rectifier that is KNOWN to possibly decay over time it's effective DC bias or offset and is also affected by load and current.

Time to review repair and upgrade info about the ZW

First understanding the metal oxide rectifier itself https://en.wikipedia.org/wiki/Metal_rectifier

" copper-oxide rectifiers tended to have poor efficiency, and the reverse voltage rating was rarely more than a few volts."

https://ogrforum.com/...er-diode-replacement

https://ogrforum.com/...w-whistle-diode-help

@Vernon Barry posted:

Simple answer, the difference between a metal oxide rectifier disk and modern electronic controlled output.

Bingo.

. . . which begs the question -- is there a fix for such a problem? I have a ZW that doesn't seem to activate a whistle tender, and suspect I may have the same problem.

@Steve Tyler posted:

. . . which begs the question -- is there a fix for such a problem? I have a ZW that doesn't seem to activate a whistle tender, and suspect I may have the same problem.

Replace the whistle diode rectifier disk with a modern silicon or even a zener diode.

Repeat of links posted earler regarding whistle diode upgrade from original copper oxide disk type.

https://ogrforum.com/...er-diode-replacement

https://ogrforum.com/...w-whistle-diode-help

Or use an external whistle or bell "box" between the transformer and the track. K-line made some good versions of them, Lionel made weak ones I don't recommend, and there are DIY options.

https://ogrforum.com/...7#138541431176529927

K-line version with some Lionel version too and DIY https://ogrforum.com/...d-or-horn-controller

@Vernon Barry posted:

Replace the whistle diode rectifier disk with a modern silicon or even a zener diode.

Repeat of links posted earler regarding whistle diode upgrade from original copper oxide disk type.

https://ogrforum.com/...er-diode-replacement

https://ogrforum.com/...w-whistle-diode-help

Or use an external whistle or bell "box" between the transformer and the track. K-line made some good versions of them, Lionel made weak ones I don't recommend, and there are DIY options.

https://ogrforum.com/...7#138541431176529927

K-line version with some Lionel version too and DIY https://ogrforum.com/...d-or-horn-controller

Thanks, I'll check it out!

The real issue here is the fact that the whistle circuit was designed when the whistle tender consumed considerable power for it's AC whistle motor.  The old PW transformers require significant current to develop enough DC offset to trigger the horn function, the modern locomotives and tenders don't provide enough load as a rule.

That's all great info, thanks everyone for the education and help!

@gunrunnerjohn posted:

The real issue here is the fact that the whistle circuit was designed when the whistle tender consumed considerable power for it's AC whistle motor.  The old PW transformers require significant current to develop enough DC offset to trigger the horn function, the modern locomotives and tenders don't provide enough load as a rule.

So, do you agree with Vernon's suggested remediation measures, or is there something else needed?

Background: I've been wrestling with this issue for several years now, ever since I upgraded to a postwar ZW (from several smaller PW transformers, one per loop, that I previously used). I was surprised to find the built-in whistle/bell switch did not activate the whistle tender I had at the time, even though direct DC (using an HO transformer) *would* activate and power the tender. I even picked up a couple of the add-on Lionel sound activation buttons to try, and dropped them (one at a time) in the circuit, using one of the smaller transformers for power, to no avail (and yes, I tried reversing the button's wires to reverse the DC polarity). I ended up creating an isolated track section on the layout, and used the DC throttle output from an HO transformer to activate the whistle tender when desired.

Fast forward to a month or two ago, when I bought a vintage Williams GG-1 with the True Blast sound system. I had to create a new loop on the test layout to accommodate the massive GG-1, which I powered with one of the small transformers. After boning up on the True Blast system, I resurrected the Lionel sound activation buttons and dropped them (back to back) into the power feed. In short, they sorta-kinda work, generally activating the horn/bell sounds but sometimes after a delay and sometimes not at all. At least judged by the immediate hesitation in the engine speed, the button's electrical offset seems to be as expected, but the GG-1's True Blast module seems to have some trouble interpreting the output of the buttons.

I have more fiddling and testing to do (trying the whistle tender on the GG-1 loop, and the GG-1 on a loop powered by the ZW), but before I do, any other suggestions on what to try to get things running/activating properly before I dive in (again!)? Thanks!

I seem to recall a mod involving a large Zener diode that was best for offering a nice healthy DC offset, but I can't find the reference to it now.

https://ogrforum.com/...-in-a-zw-transformer

Even though the title of this one is Resistance Wire- it's got answers about using Zener diodes in the ZW https://ogrforum.com/...wires-in-zw-upgrades

@GregR posted:

Install a 1N3311B 50W 12V Zener diode as a direct substitute for the original rectifier disk. Then just cut off and discard that nasty asbestos coated resistance wire. Done.

You can also get really fancy and rig a second one of these diodes backwards to get a bell button. You can install a new push button that is used to fire a relay that instantly diverts track power through the diode with 5V boost from the compensating winding. Very solid, reliable bell on/off, without voltage drop.

A little pricey over at Digikey, so maybe another vendor or alternate source. https://www.digikey.com/en/pro...logy/1N3311B/4377736 FYI, Mouser seems just as high $46 each!!!!

Yeah, Newark, $10, a lot better price SOLID STATE 1N3311B

to be fair, RS components has it too at the lower price https://us.rs-online.com/produ...wcB&gclsrc=aw.ds

Before you to tearing into things, have you played around to see if there is a "sweet spot" on your whistle switch? I have a few Williams by Bachmann units and some of them only work consistently when I finesse the whistle switch on my ZW to find the spot.

@CK posted:

Before you to tearing into things, have you played around to see if there is a "sweet spot" on your whistle switch? I have a few Williams by Bachmann units and some of them only work consistently when I finesse the whistle switch on my ZW to find the spot.

Mmm, good point. I haven't yet tried the GG-1 with the ZW, only with the separate sound activation boxes, but will be sure to wiggle the ZW's sound toggle when I try it on the main layout.

@gunrunnerjohn posted:

I seem to recall a mod involving a large Zener diode that was best for offering a nice healthy DC offset, but I can't find the reference to it now.

@Vernon Barry posted:

https://ogrforum.com/...-in-a-zw-transformer

Even though the title of this one is Resistance Wire- it's got answers about using Zener diodes in the ZW https://ogrforum.com/...wires-in-zw-upgrades

A little pricey over at Digikey, so maybe another vendor or alternate source. https://www.digikey.com/en/pro...logy/1N3311B/4377736 FYI, Mouser seems just as high $46 each!!!!

Yeah, Newark, $10, a lot better price SOLID STATE 1N3311B

to be fair, RS components has it too at the lower price https://us.rs-online.com/produ...wcB&gclsrc=aw.ds

Thanks -- sounds like there are indeed some repair/upgrade paths within the ZW. I still have some experimenting to do before I commit to major surgery -- I'd love to be able to move the whistle tender to the main lines on the layout, but I've lived with the situation long enough to be patient a while longer . . . I hope!

@Vernon Barry posted:

https://ogrforum.com/...-in-a-zw-transformer

Even though the title of this one is Resistance Wire- it's got answers about using Zener diodes in the ZW https://ogrforum.com/...wires-in-zw-upgrades

A little pricey over at Digikey, so maybe another vendor or alternate source. https://www.digikey.com/en/pro...logy/1N3311B/4377736 FYI, Mouser seems just as high $46 each!!!!

Yeah, Newark, $10, a lot better price SOLID STATE 1N3311B

to be fair, RS components has it too at the lower price https://us.rs-online.com/produ...wcB&gclsrc=aw.ds

Back when I posted about the Zeners a few years ago they were only a couple of bucks each. I’m not sure when or why they became worth their weight in gold. Probably not a good solution now!