Jim, this makes a lot of sense. I found out the hard way the transformer secondary can be pretty fragile. In my heater I found it did a great job of protecting the 2 amp fuse.
See page 10 Figure 1 in https://www.jandy.com/-/media/zodiac/global/downloads/0748-91071/6594.pdf?force=1Not sure where to test when the whole thing is unresponsive
Show us where the fuse in the your power center is. What size is the fuse?I replaced the fuse on the power center which I found was blown, but each time i turned on the power, it lit up briefly then blew the fuse. ( so much for that $6). So i think my circuit board is bad.