Lionel 1033 transformer repair and troubleshooting

Last Updated on March 27, 2023 by Dave Farquhar

As I’ve written before, Lionel 1033 transformers are well regarded because they’re reasonably high wattage (90 watts), very readily available, relatively inexpensive and pretty dependable. They really only have one design flaw: the circuit breaker. Here’s how I approach Lionel 1033 transformer repair.

The circuit breaker in my 1033 went bad a couple of years ago. I finally got around to replacing it.

First, here were the symptoms: I would turn the transformer on and run the train, but the slightest bit of arcing on the track would cause it to go dead. Or it would run for a few laps, then go dead. Dennis Brennan explained to me how to adjust the circuit breaker, but after a few months I started having problems again. Eventually the transformer just appeared to be completely dead.

Given the problems I had, it’s better to replace the breaker with a modern one. Modern breakers are inexpensive and less finicky. The last thing I need when I want to unwind by running trains at the end of the day is a moody transformer.

Lionel 1033 troubleshooting steps

First, test the 1033 to make sure the circuit breaker is the problem.

Unplug the transformer, remove both handles by lifting them straight up off their posts, and remove the four Phillips-head screws. The circuit breaker is a brass assembly between the posts and the mounts for the handles. It has a black wire soldered to the top of it.

To bypass the breaker, run a wire from the black wire on the breaker to the B post. If possible, slip the top of the case back on, then put the handle back on the post on the right-hand side. Turn the throttle up a bit and measure the voltage on posts A and U. If you see voltage, then the circuit breaker is indeed causing your problem. Unplug the transformer and take it back apart.

Adjusting the circuit breaker

At this point, you can try adjusting the sensitivity of the breaker by turning the screw clockwise no more than a full turn to see if the transformer operates better, then put a dab of nail polish on it to hold it tight in that position. But in my experience this was only a temporary fix.

Repair the Lionel 1033 transformer with a new circuit breaker

There are any number of suitable replacement circuit breakers. I used a 5 amp Littlefuse breaker as a replacement. Another suitable replacement is a Bussmann UCB-6, available on Amazon or Ebay.

To install the replacement breaker, desolder the black wire from the original breaker. Thread that wire through to the open space in the left-hand side of the transformer. Solder another wire to the lead that runs to post B, and thread it through to the open space in the left-hand side of the transformer (with the transformer posts sitting away from you). Slide a piece of heat shrink tubing over each wire, then solder one wire to one leg of the new circuit breaker, then the other. Slide the tubing down over each leg of the breaker to insulate it, then shrink it in place.

Tuck the breaker into the void on the left-hand side of the transformer. Push it in far enough to clear the case but not so far that it makes contact with the metal transformer core. Allow it to cool before trying to use it again. The heat from your heat gun or hair dryer will cause the circuit breaker to activate.

Once it’s had a chance to cool, however, your 1033, made from 1948-1956, will again work dependably, and with more modern technology.