XO Troubleshooting Guide

This is a troubleshooting guide for the XO laptop. It is geared toward troubleshooting production units running firmware version Q2D03 or greater.

Still very much a work in progress!! Feel free to add

Problems powering on

For an introduction to the different boot options selectable while powering on, see the Cheat codes.

All of these tests assume that a known good source of power is available, either a charged battery or power adapter. To debug problems with the power source, and battery charging issues, see Power and Battery problems.

Is the Power LED On ?

When the power button is pressed once, the power LED doesn't turn on.

Please try Resetting the Embedded Controller.

Does the display light up ?

When the power button is pressed once, the power LED turns on, but the screen doesn't light up

Does the boot sound play ?

If no boot sound is played, but the machine boots normally, see Audio Problems.

Is the display just showing an XO ?

If laptops powers up, but stops when just displaying the XO icon in the middle, with a single dot below it:

The laptop is failing activation

If the laptop powers up, but stops when displaying the XO icon in the middle of the screen, followed by a serial number (e.g. CSN74902B22) and three icons (SD disk, USB disk, Network signal strength), it is looking for its activation lease. This should eventually print "Activation lease not found" at the top of the screen and power-off soon thereafter.

Display problems

The backlight isn't even

In this case, a vertical pattern of light and dark is seen on the display. The difference between light and dark regions being strongest at the bottom of the screen.

There are two possible causes:

Disassemble the laptop to access the small ribbon cable from the display to the motherboard. Make sure that it is properly seated in it's connector, and properly clamped down. If the connector is broken, the motherboard will need replacement.

If the cable is well seated, then it is likely that the actual lightbar in the display has failed. This lightbar can be replaced (the display itself is probable fine.)

If replacing the lightbar fails to correct the problem, it is a motherboard problem (check the voltages across R147, R148, and R149. They should be equal. If they are not, replace the corresponding switch transistor (Q13, Q14, or Q15, respectively).

Common Procedures

Rebooting the Embedded Controller

The XO embedded controller (EC) occasionally becomes confused. To reset it, remove all power sources from the laptop:

1. Take the battery out and remove the power adapter
2. Wait 10 seconds to allow the embedded controller to lose power and reset
3. Replace at least one source of power (battery or power adapter)