On Fri, 22 Nov 2013 06:37:01 -0800, mike wrote:

Transformers often have thermal fuses inside them.
But the ones I've replaced were in the primary.

This is a pretty common transformer based on a quick google search
for the ELK TRG1640 (16.5VAC, 45VA).

They have a green LED, which no longer lights in my busted
transformer.

Interestingly, this PDF specification sheet intimates the
secondary is "auto fused" (whatever that means):
http://www.elkproducts.com/_literatu...440_Data_Sheet