20 Most Recent APC Back-UPS RS 1200 LCD - UPS - 720 Watt - 1200 VA (S7253523) UPS System - Page 9 Questions & Answers

What is the sound? Is the device working normally? Are there any lights or indicators? Do they indicate a fault or error?A UPS runs on standard 110-120 VAC power. It converts the input power to DC and charges internal batteries, then back to AC. Connected devices actually run on the conditioned 115-120 VAC output. The batteries serve as a short term backup power source.The electronics in the UPS can produce hum or high pitched tones. The sound should not be annoying. If it is louder than connected equipment (computers) it may indicate a problem. Hum is usually 60 Hz harmonics and difficult to eliminate. This harmonic may be transferred to audio equipment such as speakers or radios. A high pitched tone can be related to the rectifiers for the convertor/invertor. If the tone is loud, it means the rectifiers are drawing a lot of current. This is usually related to bad batteries.Measure the voltage on the output receptacles. It should be 115-120 VAC. Disconnect everything on the output receptacles. Unplug the UPS from it's power source. If the output power dies within 1 minute, the batteries need to be replaced.

It might some loose connections in side

got the diagram already? :)

i want to genx super scan plus 1200dpi for windows xp

this link may help there is a good section on replacing batteries and doing self test againclick here for manual

there are several reasons that will make an ups to go to bypass, which include    1. overload, check the load percentages of your loads to make sure they dont exceed 100% . check logging events
               2. ups failure, if the ups is set to go to bypass whenever it detects internal failure it will do so. but it is highly unlikey becouse they went to bypass at the same time.
              3. manual bypass, somebody is involved in bypassing.

for some ups system it is possible to see the cause of automatic bypassing, try and check in the user manual to see whether it is possible with your system. 

Without knowing which light is flashing I can only guess. From my experience and assuming it is the battery light that is lit and NOT the overload light, it can be one of two things, one is your battery is near the end of its life and needs to be replaced, and the other is that your battery is improperly connected.

To confirm if your battery needs to be replaced or not, you can run a self test. Ensure that the battery has had time to fully charge (and that it is definitely correctly connected), and then turn off the UPS, and turn it back on. It will automatically run a self test.

if the light stays lit, you need to order new batteries. One source is here: http://www.refurbups.com/APC-Back-UPS-RS-900-BR900-Replacement-Batteries

If it IS the overload light that is lit, you simply have too much equipment attached to the UPS, more than the inverter can handle. Try removing some equipment until it turns off.