ZW weirdness

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  • Member since
    November 2020
  • 3 posts
ZW weirdness
Posted by Robdawg on Tuesday, November 17, 2020 6:39 PM

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

  • Member since
    November 2020
  • 3 posts
Posted by Robdawg on Wednesday, November 18, 2020 3:47 PM

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.

  • Member since
    December 2005
  • From: Hopewell, NY
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Posted by ADCX Rob on Wednesday, November 18, 2020 8:23 PM

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?

Rob

  • Member since
    October 2020
  • From: SE Minnesota, USA
  • 24 posts
Posted by Snip on Wednesday, November 18, 2020 8:26 PM

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?

  • Member since
    December 2005
  • From: Hopewell, NY
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Posted by ADCX Rob on Wednesday, November 18, 2020 8:43 PM

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



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

Rob

  • Member since
    June 2013
  • 80 posts
Posted by smokey1 on Thursday, November 19, 2020 9:46 AM

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.

  • Member since
    December 2005
  • From: Hopewell, NY
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Posted by ADCX Rob on Thursday, November 19, 2020 12:30 PM

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.

Rob

  • Member since
    November 2020
  • 3 posts
Posted by Robdawg on Friday, November 20, 2020 1:31 PM
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.

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