APC Back-UPS XS

For more information, see this article's corresponding Wikipedia page: Uninterruptible power supply.

APC Back-UPS XS

Preliminary Information
Release Year	2000's
Leak Risk	Medium
Batteries	Ni-CAD
Mounting Technology	SMD, Through-hole
Capacitor Types	Aluminum Electrolytic
Destructive Entry	No

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.

Known Issues

UPS Unable to Power On or Charge

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.

Original Parts

Main PCB

Board Model Number TBD

Capacitor Specifications and Footprint Information

RefDes	Qty	Capacitance	Voltage	Mount	Diameter/Size	Pin Ptich	Temp	Type	Brand	Series
C3, C19, C40, C41, ??	5	22 µF	16V	SMD			105C	Electrolytic, Through-hole	KEMET

Replacement Parts

Main PCB

Capacitors

RefDes	Qty	Compatible Part Number	Order Links
C3, C19, C40, C41, ??	5	USV1C220MFD	Digikey

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.

Additional Images

• 

  Apologies for the bad state of the image. One SMD (C3.) has already been removed in this image. C41 was factory-replaced by a through-hole cap.

Apologies for the bad state of the image. One SMD (C3.) has already been removed in this image. C41 was factory-replaced by a through-hole cap.

Related Links

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