Back UPS RS 800 Startup Problem (alternates between On-Line and On-Battery)

[BillP]

I’ve had a Back UPS RS 800 for about 11 years. During that time, I’ve replaced the battery once or twice, the last being about 4 years ago. The device has worked flawlessly during this whole time and is turned on almost every day for 10-12 hours. Only one computer and two flat screens are plugged into the device.

After pressing the power button, the normal startup routine is that the On-Line LED is lit for about one second and then goes out, immediately followed by the On-Battery LED which is lit for about a second which goes out. Finally the On-Line LED remains lit and the device is ready to go, at which point I turn on the computer.

Recently, a problem has developed upon startup. After pressing the power button, the Back UPS alternates repeatedly from On-Line to On-Battery, as described below:
The On-Line LED lights for about 1 second
The On-Battery LED lights for about 1 second
The On-Line LED lights for about 0.25 of a second
The On-Battery LED lights for about 1 second
The On-Line LED lights for about 0.25 of a second
The On-Battery LED lights for about 1 second
Finally, the On-Line LED stays lit and I start the computer.

Sometimes, the Back UPS unit alternates between On-Line and On-Battery for 20 seconds before the On-Line LED remains lit. It’s almost as if a relay is repeatedly re-opened before finally latching in the correct position.

This problem only occurs at startup and once it is set for the day, the problem does not reoccur. If there is a brief power problem, the Back UPS has no problem going briefly onto battery and then back onto mains power.

The Overload LED and Replace Battery LED remain dark throughout the startup process. After turning on the computer, they also remain dark.

Does anyone know what might be the problem?

[BillP · Accepted solution]

Hi W,

I would suggest performing a braindead on the UPS. Please follow this procedure:

1: Disconnect any attached load.

2: Unplug the UPS from the wall socket.

3: Disconnect the UPS' internal battery.

4: Push and hold the ""On"" button on the UPS for 5 seconds

5: Reconnect internal battery.

6: Plug UPS in to known good power source.

7: Turn UPS on.

Regards,

Tom