ZW weirdness

[Tranz4mr.com]

I'm rebuilding another ZW right now so I thought I would try to simulate your problem.  I slipped a piece of paper between the circuit breaker contacts so no power should go out of A, B, C or D. I hooked D-U up to a train (load). When I bring up the D handle the Red light comes on. If I bring up AU the red light does not come on but AU reads 20 volts. BU and CU react the same as AU. The voltage on AU, BU and CU is there but obviously there is no current - there can't be. This is basically what happens when the breaker is bad - terminals read 20 volts but there is no power so the train doesn't move. As a test I would try temporarily jumpering across your new circuit breaker to see if it fixes your problem. Good luck

[Robdawg]

Hello all,

I replaced the circuit breaker and it still acts the same as before. What should I look for now?

Rob

[Robdawg]

All outputs (A-D) will run a locomotive. When D is touching coil, voltage to short light is 22 volts, not 6 or 8. All wiring is factory soldered, nothing seems to have been moved. Nothing seems out of place comparing to the ZW wiring schematic.

[ADCX Rob]

With nothing connected to the ZW and a faulty circuit breaker, you will get accurate outputs on all A-B-C-D.

The only reason the red lamp doesn't come on all of time - it has power, 8 volts, to one side of the bulb - but the connection to the common "U" is bypassed by a short circuit through the circuit breaker to the "U" posts. When the breaker opens, all power from the transformer to the "U" posts is diverted instead through the (red) bulb and a 60 ohm current limiting resistor, which only illuminates when a throttle is advanced, and there is a load on that throttle.

My suspicion is that the circuit breaker is in fact stuck open, and the "D" handle is the only one bleeding through a capacitive load/current enough to light the bulb, and none of the handles will power a layout.

[smokey1]

Let's see if I can explain my thinking well enough for you all to understand, Could it be that where the wire from the bottom of the roller where it is connected is touching something else at the same time giving you the short. Or where that wire goes to has a short there where it is connected. In other words, follow the wires to see. It could even be from the D post to where that connects.

[ADCX Rob]

Snip

I'm wondering if the D windings have a short.

The D windings are the same windings as A, B, & C.

[Snip]

Just a shot in the dark...

I'm wondering if the D windings have a short.

I don't suppose you have an ESR meter handy?

[ADCX Rob]

Try pulling the D arm off the windings to see if the connection is at the windings or elsewhere when the throttle is moved.

Otherwise, how well do all the controls work when connected to a layout?

[Robdawg]

I should add that the light only comes on when D is making contact with the windings and that the bulb glows at full voltage not 6 volts and does not vary with movement of D on the windings. Previous owner had in a 1449 which I thought was weird, now I know why.

[Robdawg]

Hello. I have a ZW in for cord replacement and rollers. I have done a ton of these, most with zero issues but this has got me stumped. Checking the voltage on A-C gets correct voltages. When I move D, the red short light comes on. Nothing hooked to the ZW other than the meter. The other 3 outputs did not cause the light to light. All connections are soldered well, no wires inside touching anything they shouldn't. Any and all suggestions as to what to look for would be much appreciated. Thanks!

Rob