APC Back-UPS XS

The Back-UPS is a series of uninterruptible power supplies (UPS) made by American Power Conversion (APC). Back-UPS units are line-interactive UPS systems, only running their inverters when the grid power is unavailable. The 800, 1200, and 1500 models are known to have encountered this problem.

Causes

 * The UPS failed, causing it to improperly register line voltage, and causing it to go into battery mode. Symptoms include not being able to charge, or turn on. The unit may make a chirping sound when the power is held to turn it on, but will then not turn on.

Solutions

 * Replace the five 22uF 16V SMD electrolytic capacitors on this board. There are four near the middle of the mainboard and one near the LED at the edge.

Repair Notes
When I repaired my board, I replaced the SMD caps with Through-Hole caps, which is why the Replacement Parts below contains Through-Hole Caps. I did this as a hobbyist level repair, and soldering these was easier for me. If someone else performs this repair with SMD caps, please update the info below.

I highly recommend the synaesthesia blog post (see related link below) for detailed information on this fix, including images.

Main PCB
Board Model Number TBD

Main PCB
If parts are not available or different selection is preferred, you can use the values in the Original Parts section to perform a parametric search.

Related Links

 * Blog Post by synaesthesia with great information regarding this fix
 * BadCaps.Net Forum Post
 * Wikimedia Commons Photos