The ZW I just bought at the train show yesterday is reading 3.4 volts when its handles are in the off position. Is there a way to adjust the handles so it will hit zero or is there another way to fix this problem?
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First a rattle, and now the transformer won't turn off.
If you have contact information for the seller, I'd take it back.
What was the source of the rattle?
I'd like to know more about this 3.4 volt reading.
Which terminal pairs are giving you this reading?
I suggest checking all four outputs, common(U) to "A", common(U) to "B", common (U) to "C", and common(U) to "D".
Run the control handle for each one from end to end, the voltage should start at zero and rise smoothly.
Sometimes some of the four common(U) posts don't work. While a nusance, this would not be a serious problem (easily fixed). If one doesn't work, just try another "U" post. The common posts(U) are all just strapped together inside.
Let us know what you find, and perhaps someone can diagnose the issue.
there was a piece of plastic that came lose. i put it back in place and glued it in. so that is taken care of. it was to keep the plates from moving. u&a give the 3.4, u&b gives the 3.4, u&c gives 3.4, u&d gives 3.4 volts. so all of them. any ideas?
What do they give on the "high" end?
20.4V all of them
Your high voltage reading are reasonably close, but your low voltage reading (3.4 volts) seems a bit odd. The lowest readings on a ZW should be somewhere around 6 volts. For giggles, I checked the one on my layout with a Simpson 260 VOM, and got 5.8 volts on one handle, and 6 on another.
Odd reading aside, I suggest checking the positions of the rollers on the coil. To do this:
Make certain the transformer is unplugged
Remove four screws holding the cover in place.
It might be helpful to remove the red and green pilot light caps, and perhaps the bulbs.
lift off the cover.
Set all the handles to "off"
Where are the rollers sitting?
There is a plastic "parking area" at the end of the secondary coil.
all four rollers should be on this parking area, completely out of contact with the copper wire coil.
Another test:
Put a load, such as a light bulb on the terminals being tested.
Does the reading change?
I'd like to know if the reading goes to zero, or some other lower value.
The load is the ticket here, what you're seeing is stray fields because of the high impedance inputs of the meter. This is a very common issue, and I see the same here for any totally unloaded transformer.
