Hi, I just got my 2377 and bought a second hand supernova from about 2000 vintage for £300. No cal certificate but assumed it would be o.k. to ge me up and running. Having messed about with it around the home to get a feel for it's operation before I get it cal'd and I start touting for local business it seemed to be a great machine for all my needs and with a barcode scanner had plenty of scope for expansion. However there seem to be a few niggles creeping in- first the screen locked up and I had to switch on and off to reset. Then on later testing the machine told me hat the supply had a floating earth (it didn't) but eventually settled down. On other occasions it has told me that perfectly good iec leads are l/n reversed and that the machine displayed internal relay error codes and said it was overheated after just 3 tests, only to settle down after a few minutes to test normally. It has also given lowish insulation freadings on iec leads only to retest later at much higher insulation resistance figures. Basically what do more experienced forum members feel is the problem have I bought a pup or could it be economically refurbished. My gut feeling is that it is a software problem or perhaps a knackered backup battery causing software glitches - is there a softwarevupgrade available. Thoughts. gratefully received or should I cut my losses and buy a brand new unit like one of the primetest range.