A couple of weeks ago, my Sunpower mains adapter died too.
Outout 0V. I praised myself for my foresight in ordering some
spares from the empeg store before it closed and swapped over
to a spare. I left the old one sitting on the desk.

Last weekend, I thought `I should really throw that useless
adapter away', but being the way I am, I just had to test it
again before doing something irrevocable like that. 12V.
Plugged it in to the empeg---worked perfectly.

I offer no explanation.