APC Back-UPS 1400 No Green Light and Constant Alarm [SOLVED]

[TrickyUK]

Hello,

I thought I'd post this as I couldn't find a solution for the above problem anywhere on the Internet but finally worked it out myself and it might help the next person. 

After carrying out a battery replacement turning on the power to the unit gave three green light flashes, followed by the green light going out and a constant alarm noise to occur. After checking the battery connections I noticed there are two very slim wires that run from the large capacitor to the units main circuit board. They happen to pass underneath where a protrusion in the side casing pushes into the unit on closing and one of the wires had been cut clean in half. I stripped and re-joined the two ends of the cable and the unit is working fine now but the wires are so small you might miss them on first glance.

Hope this helps someone else in the future as it took me a long time of tracing all the wires in the unit to find this issue.