If your Lionel ZW or VW transformer lights up and hums but doesn’t output any voltage on one or more of its pairs of binding posts, there’s a good chance one or more of the binding posts is bad. It’s possible to repair Lionel ZW binding posts cheaply.
By far the most failure prone part of the Lionel ZW and VW is the binding posts where the wires connect to your track. Fortunately, there’s a workaround that works sometimes. But if you want something better than a workaround, a proper repair is cheap and not difficult.
Testing a ZW
It’s always a good idea to conduct my safety test before doing anything else. If it tests out OK, continue.
To confirm where the problem is, test your ZW posts with a multimeter. Any cheap multimeter will do as long as it can handle AC. The two handles control voltage on the outermost posts. If one of the outputs is dead, try a different one of the common posts at the top. If you get voltage, the post is bad. Mark it for replacement. The common posts are all interchangeable.
If none of the commons work with a particular post along the bottom, that post is probably bad. Make sure your commons work with at least one of them, of course.
Testing without a multimeter
I have also heard of people testing without a multimeter by turning the posts. If the post continues to turn after the knurled nut bottoms out, you need to replace it. I’m not a big fan of this test because it can break a post. Then again, if it was that close to breaking, maybe it’s a good idea to go ahead and break and replace it.
You can also do a visual check after you open up the transformer. If a post separates from the copper bus like the photo to the right, it’s bad. If you see a loose black wire flopping around in the vicinity of the posts, it’s supposed to be connected to the one along the bottom that doesn’t have a wire.
Mark all of the posts that are bad, then get parts. Always get extras. My ZW had two bad posts in it and I broke a third one fixing the first two.
The original binding posts are really chintzy. The end that connects to the internal wiring is extremely thin and soft. If you overtighten the nuts, the backs tend to snap off and leave an open circuit.
You can get replacements on Ebay if you want. From the outside they look like the originals, but from the inside they attach with a durable 8-32 hex nut. Be sure to get the kind that uses a hex nut, not a rivet. The good replacements cost a little over a dollar apiece. The modern replacements are a much better design than the original.
I use an 8-32 machine screw and a nut. It doesn’t look like the originals, but it’s durable and super cheap. I can get a big box of 370 assorted-length 8-32 machine screws for less than the cost of eight binding posts.
I also think 8-32 machine screws are easier to install. Threading on a hex nut from inside cramped confines can be hard.
Either way you go, whether you use reproduction binding posts or simple machine screws, the replacement posts will be much more durable than the originals. The likelihood of them breaking again is very low.
Replacing the bad posts
To complete the repair, you have to take the top off the ZW. You won’t have to do any other disassembly. Unplug the ZW, then remove the four Phillips screws from the top. At that point, the the top lifts off easily.
A loose binding post still usually fits tightly enough into the case that it won’t come out on its own, even though it probably spins freely and relatively easily. To remove a dead binding post, I turn it a bit with a set of locking pliers to get it started. Once I manage to get a bit of a gap between the post and the ZW’s case, I gently pry it forward with a screwdriver. It takes a little bit of patience but there’s nothing especially difficult about this step. If it gets stuck, just switch back to the pliers and rotate the post a bit more to free it again. Then switch back to prying with the screwdriver.
Work slowly to avoid damaging the case, as Bakelite is difficult to repair.
Installing 8-32 machine screws as replacement Lionel ZW binding posts
Once you have the binding post out, use a pair of needle-nose pliers to work an 8-32 machine screw into the hole from the inside. A 3/4-inch screw is a really tight fit. A 1/2-inch screw fits easily but a bit shorter than the originals. A 5/8-inch screw might be a good compromise if you can find one. I like 3/4-inch screws because they’re a little bit longer than the originals and that gives me a little more room to put extra hex nuts on the posts. This lets me put more than one wire on a binding post easily when I need to, and lets me remove one without removing the other.
In the case of common posts, all you have to do is make sure the screw goes through the copper bus bar right by the posts. For the A-D posts, you’ll have to reattach the wire. This makes the job harder but it’s still doable.
Once you pull the screw through, place an 8-32 hex nut on the outside. Tighten the nut to secure the new post and hold it tight.
The combination of an 8-32 machine screw and hex nut doesn’t look like the Lionel original. But Marx used machine screws for binding posts on its transformers. I never see a broken Marx binding post.
Installing commercial Lionel ZW binding posts
If you use the commercial binding post replacements, thread it through from the outside, then attach the wire to the post and secure it with a nut. It takes some fumbling around and you need small hands, extraordinary coordination, or both to do it without taking out the ZW core.
After you replace the binding posts, replace the top. Secure it with the four screws. Test all four pairs to make sure you have power before you connect the transformer back to your layout.
Wrapping up Lionel ZW binding post replacement
Replacing ZW binding posts shouldn’t take you more than 30 minutes, and it’s cheap. If you have a quantity of 8-32 nuts and bolts on hand, it might not cost you anything out of pocket either. If the case is looking a bit dirty and dull and you’d like to spruce it up, here are some tips for cleaning and polishing Bakelite.
And now that you have your ZW working again, you may enjoy my Lionel ZW wiring tips.