XO Troubleshooting Guide: Difference between revisions

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{{OLPC}}{{Translations}}__NOTOC__
This is a troubleshooting guide for the [[Hardware_specification#Laptop_Hardware|XO laptop]]. It is geared toward troubleshooting production units running firmware version Q2D03 or greater.
This is a troubleshooting guide for the [[Hardware#XO_Laptop|XO laptop]].
While this is intended for use in a repair center, most of the procedures can be followed by users to [[Repair|repair]] their laptops.


==Powering on==
''Still very much a work in progress!! Feel free to add''
If you are having problems getting the XO to power on, see [[XO_Troubleshooting_PowerOn|Troubleshooting Power On]]. The [[Startup Diagnosis]] page also describes how end users (not repair centers) can debug power-on or boot problems.


==Display==
=Problems powering on=
If you are having problems with the display on an XO laptop, see the [[XO_Troubleshooting_Display|Display diagnostics section]].


==Power and Battery==
For an introduction to the different boot options selectable while powering on, see the [[Cheat codes]].
If you are having problems such as:
* the battery is not charging
* the battery is suddenly losing charge
* the laptop won't run from a power adapter


Then you should view:
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|Power and Battery problems]].
* [[XO Troubleshooting Battery]], if you believe the problem is contained within the battery itself, or
* [[XO Troubleshooting Power]], if you believe the problem is contained within the laptop (e.g. charging circuitry, power input circuitry), or
* Both of the above, if you are unsure where the problem is localised.


==Network==
==Is the Power LED On ?==
If your laptop is having trouble connecting to other laptops or the Internet, see the [[XO_Troubleshooting_Network|Network diagnostics section]].
When the power button is pressed once, the power LED doesn't turn on.


==Audio and Camera==
(insert photo of 'stuck' power button vs. 'unstuck' power button)
If you are having problems with the audio (microphone, speakers, headphones, or microphone input) or camera on an [[Hardware#XO_Laptop|XO laptop]], see the [[XO_Troubleshooting_AV|AV diagnostics section]].


==Keyboard and Touchpad==
Please try [[#Rebooting_the_Embedded_Controller|Resetting the Embedded Controller]].
If you are having problems with the keyboard or touchpad on an XO laptop, see the [[XO_Troubleshooting_Keyboard|Keyboard diagnostics section]].
==Touchscreen==


See the [[XO_Troubleshooting_Touchscreen|Touchscreen section]].
If that doesn't work, test that the power adapter and battery used in the test are working (using another laptop). A laptop may be unable to power itself from its battery or power adapter (for a number of reasons).


==USB==
If both power sources are working, then the motherboard is broken. The possible failure modes are numerous, and deserve a second troubleshooting guide.
If you are having problems with the USB interfaces on an XO laptop, see the [[XO_Troubleshooting_USB|USB diagnostics section]].


==Debugging Procedures==
==The display doesn't light up==
The following are common debugging and test procedures:
When the power button is pressed once, the power LED turns on, but the
screen doesn't light up.


* [[XO Full Reset|Rebooting the Embedded Controller]] - This completely resets a laptop
===Display dark and the boot sound plays===
* [[XO_Self_Test|Hardware Self-Test]] is included in the [[Hardware#XO_Laptop|XO laptop]].
If the display doesn't light up, but the boot sound plays, see [[#Display_problems|Display Problems]].
* [[Cheat codes|Boot options]] - Different boot options are available through pressing buttons around the screen during the initial boot process (immediately after pressing the power button). A sampling (more at [[Cheat codes]]):
** '✓' (check) game pad key: forces a more detailed display while booting. See [[XO_Troubleshooting_PowerOn#The_display_is_showing_an_XO_icon|Troubleshooting Power-On]] for more details. This is useful for debugging activation problems.
** 'O' game pad key: alternate between the current boot image and a previous one. In laptops which have never been upgraded, there is no previous boot image to use.
** Rocker left: run the [[XO_Self_Test|hardware self-test]].
* A [[Serial_adapters|serial adapter]] is very useful for debugging dead laptops


==Repair Procedures==
===Display dark and no boot sound plays===
The following are common repair procedures:
This usually indicates a broken motherboard or a Real Time Clock battery problem in conjunction with early firmware.


* [[Reuse checklist|Summary Refurbishing & Reuse Checklist]]
Early production machines had firmware version Q2D06, which had a bug that caused the machine not to start if the Real Time Clock chip's date had been reset to 0. This could happen if that chip lost all power, including its backup power from an internal "coin cell" battery. To make matters worse, some of the early units were manufactured with defective holders for that coin cell battery, so that the battery could became loose or even pop out entirely. To determine conclusively that this is the problem, you must open the enclosure, and to repair it you will need special tools as described below. To diagnose the problem, open the enclosure. If the coin cell battery is loose or out of its holder and the system is an early production unit, this is probably the problem. To be completely sure, you must connect a serial terminal to J1 on the motherboard, via a special low-voltage interface adapter. If the system has this problem, you will see "Page Fault" on the serial console shortly after power up.
* [[Motherboard Handling Procedures]]
* [[Disassembly|Disassembly Guide]]
** [[Disassembly_top|Getting at the display and motherboard]]
** [[Disassembly_bottom|Replacing a keyboard/touchpad]]
** [[Screws|Guide to screws]]
* Motherboard Guides: [[XO Motherboard|intro]], or [[XO_Motherboard_Repair|repair]]
* [[Activation_and_Developer_Keys|Getting a developer key for a laptop]]
* Using an XO as a serial terminal on either [[Serial_adapters#Linux|Linux]] or [[Firmware/Serial_Terminal|Open Firmware]],
* [[XO_Flash_Bad_Blocks|Finding and fixing bad blocks of NAND Flash]]
* [[SPI_FLASH_Recovery|Replacing/Recovering the EC (SPI) Flash]] - Replacing the [[Embedded_controller|Embedded Controller]] Flash
* [[Fix_Clock|Fixing an RTC problem]] - Fix laptops which can't boot due to reset RTC time.
* [[XO_LiFePO4_Recovery_Procedure|Fixing LiFePO<sub>4</sub> batteries that stop charging]]
* [[XO_Power_Diagram|A detailed description of the laptop power circuitry (XO-1)]]
* [[Memory Bit Mapping]]


[[Category: Repair]]
====Repairing a "bad RTC setting" system====
[[Category: Hardware]]

[[Category:XO-1]]
Repairing a system with the "early firmware, bad RTC setting" problem requires several steps. If you have lots of XO machines, you might consider using the bad system for spare parts. Otherwise, you can repair it as follows:
[[Category:XO-1.5]]
* First, you must re-seat the coin cell battery in its holder and secure it so it doesn't come out again. One way to secure it is to put a drop of glue where the battery contacts the holder, away from the metallic contact. The best glue that I have found for this purpose is clear solvent-based household cement. Technically, it is "nitro cellulose" cement. It is also known as "model airplane glue", marketed under various trade names such as "Duco Cement" and "Tarzan's Grip". Stronger adhesives like epoxy or cyanoacrylate (super glue) would probably work too, but it might be difficult to remove the battery later without damaging the holder.
[[Category:XO-1.75]]
* After securing the battery, you must replace the boot firmware with a version that is newer than Q2D06 (use the latest official release). There are two ways:
[[Category:XO-4]]
# Option 1 requires electronic rework (soldering and desoldering) skills and tools, and access to a standalone SPI FLASH programmer device. You unsolder the SPI FLASH chip, reprogram it (or a new one) with a recent firmware version, then resolder the fresh chip.
[[Category: Developers]]
# Option 2 requires a serial terminal with a low-voltage interface adapter that will connect to J1 inside the XO. The steps are:
## Insert a USB key containing the new firwmare version.
## Connect the serial terminal (115200,8,n,1) and power on the machine. You should see "Page Fault" on the serial terminal, followed by an "ok" prompt.
## Type the following command line at the ok prompt, substituting the correct .rom filename:
ok probe-pci probe-usb flash u:\q2d14.rom
After you have updated the firmware, you must set the RTC clock. There are several ways:
* If you can boot to Linux (because the machine is permanently activated or you have a developer key), you can use the Linux "hwclock" command.
* If you have an open wireless network that is connected to the internet, you can type this at the ok prompt (replacing "MY SSID" as appropriate):
ok ssid MY SSID
ok ntp-set-clock
* Otherwise, you can use OFW to set the date as follows. First determine the date and time in UTC, then:
ok select /rtc
ok decimal 0 10 22 27 5 2008 set-time
ok unselect
The above example is for 2008-5-27 22:10:00 UTC, i.e. the numbers are entered starting with the least significant - second, minute, hour, day, month, year.
* If you can't get to the ok prompt in the normal way because the machine is secure and you don't have a developer key, you can still set the date via a serial terminal. Power up the system and immediately start typing "iiiiii..." on the serial terminal. You should get an ok prompt within about 2 seconds. (You can't reflash the firmware from this ok prompt, but you can set the clock).
Erase any extra 'i' characters with Backspace, then type the "select /rtc ..." command sequence as shown above.

=== Machine boots normally, but no boot sound plays===

If no boot sound is played, but the machine boots normally and has audio, it is likely that the user has changed the default boot volume to 0. While the boot sound is playing, a user can adjust the volume using the ''volume adjust'' keys. This modified volume setting is saved and used for future boots. Try increasing the volume right after starting the laptop a few times, and see if the boot sound returns.

If no boot sound is played, and the machine boots normally but has no audio see [[#Audio_problems|Audio Problems]].

== The display says "Connect to power to proceed" ==
''Not quite the correct wording. Anyone remember the exact words ?''

Early versions (before Q2D14) of the firmware would stop execution if a firmware update was scheduled, but two sources of power (a battery and a power adapter) aren't present (
[[http://dev.laptop.org/ticket/5422|Trac #5422]]). If this is the problem, provide both sources of power and reboot. The laptop should proceed with a firmware update and boot normally.

==The display is showing an XO icon==
This means that Open Firmware has started the boot process.

===XO icon with a "sad face"===
This means that Open Firmware couldn't find a signed operating system on the internal flash memory. (It will also look on USB memory sticks and SD cards.)

You can get more information from Open Firmware by holding the "check" button (above the power button) after powering on. That will make Open Firmware display more detailed messages about what it is doing during the secure boot process. The messages are in English only.

Try [[Secure_Upgrade|upgrading or re-install the software]].

===XO icon with a single dot below it===
If laptops powers up, but stops when just displaying the XO icon in the middle, with a single dot below it, it means that something is wrong when the Linux OS starts operation. Try booting with the

One solution to try is [[Secure_Upgrade|upgrading or re-install the software]].

===XO icon with a serial number and three icons below it===
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.

The solution is to re-activate the laptop. Obtain a copy of the lease (or a new lease) from your country activation manager, place it (named "lease.sig") on the root directory of a USB key and boot the laptop. See [[Activation_and_Developer_Keys#What_to_do_when_You_Receive_Your_Activation_or_Developer_Keys |What to do with your activation keys]].

=Display problems=

==The display doesn't turn on==

Use a strong light shining on the display to confirm that the problem isn't that [[#The_backlight_won.27t_turn_on|the backlight won't turn on]]. If you see text or graphics on the display, the problem is with the backlight.

Use a known good display to check whether the display or the motherboard is broken.

If the known good display also does not turn on, the motherboard is broken and should be replaced.

==One half of the display looks bad==

===Is the display cable properly connected ?===
Disassemble the laptop to access the larger flex cable from the display to the motherboard. Make sure that it is properly seated in its connector and properly clamped down. The white stripe on the cable should be close to and parallel to the black tab clamping the cable down.

''Photo needed here, a closeup of the display connector''

If the connector is broken (the small black tab fails to stay in place), the motherboard will need replacement.

===Is the display broken ?===
Use a known good display to check whether the display or the motherboard is broken.

If the known good display shows the same problem, the motherboard is broken and should be replaced.

==The display fades to white==


==The backlight won't turn on==


==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.

===Is the backlight cable properly connected ?===
Disassemble the laptop to access the small flex cable from the display to the motherboard. Make sure that it is properly seated in its connector, and properly clamped down.

''Photo needed here, a closeup of the backlight connector''

If the connector is broken (the small black tab fails to stay in place), the motherboard will need replacement.

A temporary solution is to wind a small strip of paper several times, jamming a small piece of it into the connector to hold the flex cable in place. A piece of tape covering the connector provides additional stability.

===Is the lightbar broken ?===
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 probably fine.)

===Is the motherboard backlight driver broken ?===
If replacing the lightbar fails to correct the problem, it is a motherboard problem. Check the voltages across R147, R148, and R149 when the backlight is operating. They should be equal. If they are not, replace the corresponding switch transistor (Q13, Q14, or Q15, respectively) with a generic NPN low power switching transistor (2N3904 equivalent).


=== Do all led's light up ? ===

test: Open the the screen. (2 tiny screws) reconnect cables boot up the XO. Some led's ligth up, some don't.

fix: resolder broken leds.

=Audio and Video problems=

A stereo sweep pattern is output for testing the speakers/headset jack when running the Open Firmware hardware tests. A microphone test, where audio is recorded, then played back (at low volume) is also included. See [[#Hardware_Self-Test|Hardware Self-Test]].

==No sound through the speakers==

==Garbled sound through the speakers==

==No sound through the headphones==

If the speakers function correctly, this is caused by the headphone connector.

==The microphone doesn't work==

==The microphone jack doesn't work==


==Images from the camera are black==

=Keyboard and Touchpad problems=

==Does the keyboard generate unexpected responses ?==

#''Stuck keys''
# bad connected cables

==Does the touchpad only allow vertical (horizontal) movement ?==

=USB problems=

A full set of eye patterns is generated for testing the wiring of each USB port when running the Open Firmware hardware tests. See [[#Hardware_Self-Test|Hardware Self-Test]].

==One of the USB ports doesn't work==

This is typically due to broken connector or solder joint at the affected connector.

All of the USB ports receive power from a common switch, so if there is a problem with power it is likely due to the above reasons.

==None of the USB ports work==

Measure the +5V supply at the USB connector (or across C509 or C551). If it is not present, the USB power switch and current limiter, U56, may be broken. It may be bypassed by a 0 ohm resistor at R466 for testing purposes.

If the audio (speakers) is also non-functional, then the problem is the +5V supply on the motherboard.

=Power and Battery problems=

==The laptop won't run using the battery==

==The laptop won't run using the power adapter==

==The laptop emits a high pitched whine when using the power adapter==

==The laptop can't charge the battery==

# sign: The charging led it burning yellow and never gets green.
# debug:
## check if battery connector in the chassis has 7 volt.
## check if battery connector on the motherboard as 7 volt.
## If the has If This is due lose cable / connector. check wiring and connectors st
# fixes:
## bewing pins in the connectors
##resolder / replace wires

=Common Procedures=
==Rebooting the Embedded Controller==
The XO embedded controller (EC) occasionally becomes confused. To reset it, remove all power sources from the laptop:
# Take the battery out and remove the power adapter
# Wait 10 seconds to allow the embedded controller to lose power and reset
# Replace at least one source of power (battery or power adapter)

The battery LED should flash orange momentarily (about a quarter of a second) when power is first reapplied. If you do not see this flash, you either have a motherboard hardware problem or faulty EC firmware installed. The general solution to both of these problems is to replace the motherboard.

==Boot options==
Different boot options are available through pressing buttons around the screen during the initial boot process (immediately after pressing the power button). These are included here for completeness. More information is available at [[Cheat codes]].

* '✓' '''(check) game pad key:''' forces a more detailed display while booting. See [[Startup Diagnosis]] for more details. This is useful for debugging activation problems.
* 'O' '''game pad key:''' alternate between the current boot image and a previous one. In laptops which have never been upgraded, there is no previous boot image to use.
* '''Rocker left:''' invoke hardware self-test.

===Hardware Self-Test===
Open Firmware includes hardware diagnostics routines for most major components of the laptop. It is triggered by pressing down the left hand side of the "Rocker switch" to the left of the screen while booting a laptop.

The following components of the laptop are tested sequentially by the hardware diagnostics:

* Battery - The current status of the battery is read from it and printed out
* SPI flash - The manufacturing data of the laptop is printed out
* Memory - The SDRAM on the motherboard is quickly tested.
* Processor - The Processor is exercised. Press any key to skip to the next test.
* USB - The USB ports are exercised (for use with an oscilloscope).
* Audio - A stereo sweep is output over the speakers (headphones, if plugged in) and then audio is recorded using the microphone, and output (and low volume) over the speakers.
* Camera - Video is displayed on the screen from the camera for twenty seconds
* SD Storage - Any SD storage is quickly (and non-destructively) tested
* NAND Flash - The motherboard's internal NAND Flash storage is quickly (and non-destructively) tested.
* Display - The display is only marginally tested with color bars, then the drawing capabilities of the CPU are displayed for a while. Press any key to skip to the next test.
* WLAN - The firmware is loaded, the network co-processor booted and communicated with.
* RTC
* Timer
* Touchpad - Press any key to exit.
* Keyboard - Press ESC to exit.

If using firmware later than Q2D08, you can pause between individual tests by holding down the "rotate" button on the left hand side of the screen (below the "Rocker switch").

Latest revision as of 05:09, 28 October 2013

  This page is monitored by the OLPC team.
  english | español HowTo [ID# 293344]  +/-  

This is a troubleshooting guide for the XO laptop. While this is intended for use in a repair center, most of the procedures can be followed by users to repair their laptops.

Powering on

If you are having problems getting the XO to power on, see Troubleshooting Power On. The Startup Diagnosis page also describes how end users (not repair centers) can debug power-on or boot problems.

Display

If you are having problems with the display on an XO laptop, see the Display diagnostics section.

Power and Battery

If you are having problems such as:

  • the battery is not charging
  • the battery is suddenly losing charge
  • the laptop won't run from a power adapter

Then you should view:

  • XO Troubleshooting Battery, if you believe the problem is contained within the battery itself, or
  • XO Troubleshooting Power, if you believe the problem is contained within the laptop (e.g. charging circuitry, power input circuitry), or
  • Both of the above, if you are unsure where the problem is localised.

Network

If your laptop is having trouble connecting to other laptops or the Internet, see the Network diagnostics section.

Audio and Camera

If you are having problems with the audio (microphone, speakers, headphones, or microphone input) or camera on an XO laptop, see the AV diagnostics section.

Keyboard and Touchpad

If you are having problems with the keyboard or touchpad on an XO laptop, see the Keyboard diagnostics section.

Touchscreen

See the Touchscreen section.

USB

If you are having problems with the USB interfaces on an XO laptop, see the USB diagnostics section.

Debugging Procedures

The following are common debugging and test procedures:

  • Rebooting the Embedded Controller - This completely resets a laptop
  • Hardware Self-Test is included in the XO laptop.
  • Boot options - Different boot options are available through pressing buttons around the screen during the initial boot process (immediately after pressing the power button). A sampling (more at Cheat codes):
    • '✓' (check) game pad key: forces a more detailed display while booting. See Troubleshooting Power-On for more details. This is useful for debugging activation problems.
    • 'O' game pad key: alternate between the current boot image and a previous one. In laptops which have never been upgraded, there is no previous boot image to use.
    • Rocker left: run the hardware self-test.
  • A serial adapter is very useful for debugging dead laptops

Repair Procedures

The following are common repair procedures:

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