I am building my layout for DCC. I have not purchased the system yet. I am building a MDC hon3 loco. It is ready to test. Can I use a old Lionel tranformer with a couple of test leads to check it out. I was told make sure it runs well before installing the decoder.
NO!
A transformer will provide AC, and pretty much everything other than O-gauge uses DC if it's not either DCC or DCS. You may damage your engine if you try to run it on AC.
If you aren't ready to buy your DCC system, I'd recommend finding a 12-volt DC power supply. I have several hefty 4-amp DC supplies. I use them for layout structures and streetlamps, so it's the kind of thing you're going to need later on anyway.
It takes an iron man to play with a toy iron horse.
Thank you!
For a brief test, you can connect your test leads to a six volt lantern battery (that big boxy-looking thing with the spring terminals on top) or a nine volt battery like the one used in a smoke detector. The object is simply to establish that the mechanism runs smoothly, not to operate a switching puzzle.
A Lionel transformer puts out up to 18VAC. DC motors will smoke on a lot less - and they WILL smoke on anything more than a millisecond of AC.
Chuck (Modeling Central Japan in September, 1964)