I got a Malibu 600 watt transformer. Model ML600TW. When I rotate the
on/off knob, it makes the sound of smacking the outer housing with a stick.
A loud audible clank. Then it hums.

When I apply the tester to the bottom connectors, I can't get it to read
anything. Double checked tester with various voltage alkaline batteries on
DC, and they tested fine, so tester is good.

Is this transformer fried? Is the humming normal? Is that clanking noise
normal?

Steve