1250 smart ups makeing grinding noise

[Anonymous user]

i have a 1250 smart ups 900watt, just recently put new batterys and the system is been serving me for atleast 15 years now not a problem, but i have just started noticing when it goes offline from utilty powere and there is a load on the unit, it intermitdly makes a loud grinding like sound every so often till the power kicks back on, i have checkd to see if its the fan and it is not the case so i dont know what the problem is, i am not willing to buy another unit as it still works fine and has out performd any new system i have encounterd. if anyone can help it would be greatly aprechiated.
it has 2 12 v batterys 18volt amps each.
the load bar is only at one when i recorded the sound 1 bar is about 17% load or les so i dono whats going on help please

[Anonymous user]

well i knoe people have repair books for them cause i have found one b4 and posted on here a few years ago, for me to just stop useing the systems would just be a waste of 200$ spent on batterys, and apc trade trade program only works if u still have proof of ownership and as i said i have had this unit since the good ole 90's so i have long since lost all paper work on it. eavn if i could trade up i wouldnt because i have had newer systems less reliable and die wile in use and all apc did was send the a identical one to me each time and each one of them died, the run times were discusting short. theres a saying older is sometimes better, and for good reason. so if someone who has a better salotion for me or refrence manule can help it would be nice.

[Anonymous user · Accepted solution]

this unit was desind with 386 tech in mind and old servers with todays technoligey it can run 3 servers 2 floresent lamps my tv my desktop, i have not found another system capible of this for run times of a few hours that would be under a grand i paied 1200$ for this system when it was releasd it still works fine still giving clean undisrupted power just the inverter makes a noise, is it normal with age for it to make noise? i meen its very valueble to me and always been there when i needed it, hell the thing can run my fridge. lmao