Thanks Steve,
not sure about PA 800, but my PA3x had a battery pack.
All it did on the pa3x was help start it up more quickly
I hadn’t used it for over a year, and couldn’t workout why it took ages for it to boot up.
Penny finally dropped, dead battery pack. I took the pak out, Pa3x still kept booting up , albeit slowly.
I finally managed to find a place that still sold them in the USA, they shipped it over, PA3 x back to normal.