This failed CW-40 has ended up in my possession. The owner traded it to my train-repair friend towards an older Lionel transformer with a higher rating. When I have more time I'll try figuring out the full extent of the failure.
FEC fan mentioned "The most likely part blown is the triac." I'd like to test that just out of curiosity.
As gunrunnerjohn observed, it takes a long shank to reach the "security screws", and we ground our own.
GGG, the component formerly at the location labelled "C1" is totally vaporized and it burned some of the circuit trace. When I tried jumpering a small capacitor across it, it burned more of the trace.
The transformer component tested OK so I could easily adapt the unit to a fixed voltage supply, or use a voltage regulator circuit to create a variable DC supply. But it's way down my list of pending projects!
Thank you all for your input.
