Question about a post war 275watt ZW

Are the contact fingers on the switch making a good connection?

The rectifier discs will blow modern horns. My ZW still has the discs and blows railsounds horns/whistles without issue.

Have you tried moving the lever only half way?

I had some modern era whistling tenders that would not blow with a ZW whistle control. They were the separate sale tenders with an mechanical whistle (can motor) and a circuit board to activate. The number is 16673.

I like Chuck's suggestion to try moving the control halfway.
I am wondering whether your rectifier / diode is bad.

I have ZWs (and other transformers) with original rectifier disc that work on modern equipment as well as ZWs (and other transformers) that have been upgraded with 1N1190AR type diodes.

As others have said, there are two whistle/horn positions. I find my modern electronics are most reliable with moving the control half way on a ZW.

As others have said, there are two whistle/horn positions. I find my modern electronics are most reliable with moving the control half way on a ZW.

That is the "pickup" position. The whistle control was never meant to be left in that position, which puts the full load through the rectifier. When in the "holding" position, a resistor is placed in parallel with the rectifier, sharing the load.

Is using the whistle control in such a fashion problematic? ----- I don't know.

 

C W Burfle posted:

As others have said, there are two whistle/horn positions. I find my modern electronics are most reliable with moving the control half way on a ZW.

That is the "pickup" position. The whistle control was never meant to be left in that position, which puts the full load through the rectifier. When in the "holding" position, a resistor is placed in parallel with the rectifier, sharing the load.

Is using the whistle control in such a fashion problematic? ----- I don't know.

 

Yup. The half way position also slows trains. You don't get the boost from the full position.

Oddly enough all my RailSounds II/III locomotives will trigger with the whistle lever on full, but my Williams and MTH locomotives need it in the half way position. It's like Lionel engineered there stuff in the 90's to work with a ZW.

The diode and stud rectifier are new parts, since I do get a voltage increase of about 5v I would say they are good parts...

Marty

The 5v increase does not definitively indicate the health status of the diode/rectifier.

Have you tried several locomotives to see if it's a problem for all of them?

The diode and stud rectifier are new parts, since I do get a voltage increase of about 5v I would say they are good parts...

Did you use heat sinks when you soldered the wire connections?
Heat can damage them.
It's not clear to me why you would have both.

I have a 1044 with a stud rectifier in it and it works good, so problem to me seems to be in ZW whistle switch...

Marty

I have a 1044 with a stud rectifier in it and it works good, so problem to me seems to be in ZW whistle switch...

When it left the factory, the five volt boost was wired in series with the rectifier disk. In an earlier post, you mentioned seeing the 5 volt increase.  Maybe your switch isn't wired correctly.

You can test your rectifier / diodes with an ohmmeter. Set your meter to it's lowest range for ohms. With the transformer unplugged, and the control handles set to zero, touch one lead to each side of the rectifier. It may or may not show any value. Exchange the two leads.
If it showed a value before the exchange, it should not show a value afterwards.
Conversely, if it did not show a value before the exchange, it should show a value afterwards.
If it always shows a value, or never shows a value, then there is an issue.

One more comment: The original Postwar Lionel whistle control systems often would not generate enough DC offset to operate the whistle relays when there was insufficient load on the transformer.
If your trains are all modern era units with can motors, that could be your issue.

The answer for Postwar was to increase the load by either adding more cars to the train, or hooking up additional loads, like light bulbs (not LED's) on the same circuit as the train.

Many folks try to test postwar whistling tenders with nothing else on the transformer. Sometimes they work alone, other times not.

The Lionel test benches that had internal whistles to test transformer whistle controls (instead of meters) had an extra coil to increase the load on the whistle control under test.