ZW Whistle Controls Reversed

Classic Toy Trains Forum
1

I have a problem with the whistle controls on my Post War ZW transformer. The whistle controls would not activate any whistles/horns for as long as I can remember. I compared all the wiring with another ZW I have which works properly and they are both wired exactly the same. I installed diodes in both sides of the non working ZW and now the whistles function, but the controls are reversed. All whistle units have been tested and work fine with another ZW I have.

When I connect the “A” throttle to the track and apply power to the track and push the right whistle control forward, the whistle clicks but will only activate for a millisecond. When I push the left side “D” throttle lever forward, the whistle works great. The same holds true if I connect the “D” throttle to the track. It seems the “D” throttle control is powering the “A” whistle control and vice versa. Any help would be greatly appreciated. Thanks.

2

[#welcome]

Lionel made two versions of the post war ZW transformer, a 250 watt(1948 to 49) and a 275 watt(1950 to 66) version. I have been told that the only differance was how it was rated and the name plate, so if you were to look inside it should be the same, but that may not be the case. The problem might be as simple as switching the wires on the diode units.

To repair something you should have a schematic diagram, especially when it comes to electrical stuff.

Lee F.