So, decided to test this UPS, dating from 1997. Open the case, and look at the battery inside, stone dead Panasonic, likely good only as a brick. Put in a new used one, at least it holds charge, and turn on the power switch. UPS starts up, and runs, so I look, mains fuse missing. New 5A one into the holder, and it powers up, charging the battery, at least for 30 seconds.
Then a puff of smoke, and a loud pop, and the Rifa blew it's top, letting the smoke out. Now I have to remove that board, replace the 3 Rifa transparent caps on there, and replace them, along with a new fuse, and I will have a nice little UPS to place on the CCTV system. Lives up to it's name of being a Scamp.......