SMT750I - "Output Off by: Software"

[peterpavlik_apc]

Hello, I have replaced batteries in APC Smart-UPS 750 and experience a strange problem related to output.

After some time online UPS disables output by itself and refuses to enable it again. After manual power-on it beeps, output is enabled for 2 seconds (green led on) and then the light and power output is disabled with message: "Output Off by: software".

There is nothing connected to UPS via USB cable, batteries are charged to 100% (26.8V), UPS powered by line (243-246V). Can't figure out which "software" is constantly turning my UPS output off (UPS firmware is 09.4 ID 18, no card & no USB cable installed).

The only solution working is the UPS brain-dead procedure. Then the output can be enabled again and works usually up to 12 hours before it's disabled by UPS again. During the time online self-tests pass without errors, no false switching to Battery, all works normally. Only issue i can see is that the green eco-mode is never activated. New Panasonic LC-R127R2PG1 batteries have been charged to 100% in the UPS about 3 times.

Can anyone please explain to me what can be the problem reason? Thanks a lot

[BillP]

Hi,

Is there a network card installed in the UPS, or, is the serial cable attached? The serial cable is RJ50 on the UPS end and 9 pin serial on the PC side. Either the network card or software communicating over serial could be the issue. 

[peterpavlik_apc · Accepted solution]

Hi,

No, no card installed in the slot and no cable connected. That's why the message is strange.

I have decided to try to replace batteries with other model. Maybe the temps were too high (35+ Celsius) and UPS decided to the disable power output.