UPS and downs : ups restarts pc !!!

[klinux]

ok just got back my ups from in-warranty service . now the problem is , whenever i turn off the main and run on the ups , it works fine , but when i turn the power back on while the system is running , it restarts for some reason . i ran with just barebone m/b and monitor , still the same problem . switched off ups while in bios , works fine , turn main on it restarts . which is the culprit ? UPS /SMPS or M/B . even cleared cmos and updated the bios .i just have monitor and system connected to the ups .

Config A7V8X-MX/2600+/512/17' samsung/zebronics 350watts

ups specs
Cyber UPS
500 VA with built in var
voltage : 150 VAC - 275 VAC
Battery 12V 7AH SMF-One

[freshseasons]

Configure UPS service for Manual startup in Administrative Tools / Services. Check settings
Check UPS signal polarity and test if it is not set to negative for power failure or restart.
Please tell if this helps.
Merry Christmas

PS : your Post on mobile Usage was good . Appreciated a lot !!

[klinux]

thanks and thanks .

. i tried with ups service enabled and disabled , same result . i get the prob in linux too and while running the pc without any drives and just into bios . wierd thing was , when the service center tested the ups after repair few days back , they attached a bulb and tested it . the bulb went bright and low when he switched back and forth . it didnt go out completely but brightness changed . i suspect voltage fluctuation or do upses normally do that ??

will run a few more test . how do i test for earthing/grounding problems for smps/pc/ups ?? i got light shock from pc plug attached to smps when i removed it from ups and touched it accidently . was weird koz the system wasnt connected at all .