Good catch on the circuit breaker, that is a logical place to start. That's why I linked the maintenance manual, you can trace things out that way.
On several KW's, I've had high resistance at the spring loaded contact point where the two wipers connect to the rest of the circuit. A shot of DeoxIT D5 in there seems to solve the problem. The hub would actually get pretty hot under a steady 8A load, and it would be dropping almost a volt across the connection. After the shot of spray, I had trouble measuring the voltage drop, but it was tiny.
There's a 100% chance that the answer is yes. The circuit breaker or it's connection to the "U" posts is the problem, the power at C-D is the giveaway - that circuit is not breaker-protected.
You may also need new carbon rollers and and cleaning as part of a regular maintenance ritual. This is important because the transformer will continue working even if the rollers are worn down to nothing, broken, or missing, causing damage to the secondary windings.
Rob
There's a 99% chance that the answer is yes. Sounds like the wipers are the problem, first step is to pop the top and check the mechanics. You may also need new carbon rollers, a common issue with these. My guess is it's a mechanical issue in the switches or the wiper connections.
Here's a link to the Lionel KW Service Manual, that should help.
Picked up a KW free ... It hums when plugged in and I can get power from C and D but nothing from A-U or B-U.
Can this KW be brought back to life?
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