Doorbell Help

I am trying reinstall a doorbell. I have 120 from the breaker to the transformer. Then when I hook up the wire to the doorbell and chime the transformer is blowing.

I had tested the continuity of the line to the bell, as well as the line to the chime. Everything looks good.

I have tried to wire the bell straight to the transformer bypassing the chime ...blows the transformer. I have tried a differnet set of wires in the run....blows the transformer.


Any ideas?