HP Pavilion Laptop Black Screen

Had this laptop that persistently just showed a black screen when cold booting.  I knew on a good boot the Caps Lock light would come on steady for a second or two then flash twice as well as the Power and F12 button lights will be on.

Then occasionally it would fire up.  I realised the only thing changing was the position I opened the screen to.  So I tried with the screen wide open and it booted!

Now, it’s not 100% successful, it doesn’t work every time.  But it points to the cables wearing out where the lid is continually shut and re-opened.

So if your Caps Lock light does ‘not blink’ or ‘not flash’  try moving the angle of the screen.

Not Out of the Woods

This worked for a while but when the HP Pavilion went into sleep mode the screen trick was no help.  There is a lot of talk on the internet forums about poor lead-free soldering of these Chinese laptops.

I decided to leave the laptop on a window ledge in a the hot sun.  After several hours I gave it another go and Wham! it booted!  This endorses the poor solder joint theory.

Screen Position

Now this makes me wonder whether opening the screen out is maybe just distorting the motherboard that helps make the dry joints work.

Also, the sleep mode would allow the HP hardware to cool down and perhaps this is where it fails to wake and be able to utilize the screen.

Warm Up!

As I thought, overnight the laptop had cooled down and would not fire up again.  But this time the Caps Lock light was on solid.  So I left it on put the lid down AC power in and let it heat up for about 20 minutes.

Shut it off with the power button 5 second press, pressed the power button again and Bingo! it booted up. So yep, it’s a dry joint issue that a bit of heat will correct.

Side-ways Approach

Interesting, overnight I left the HP Pavilion switched off and unplugged on end, propped against the wall (left side down). Put it back on the worktop, pressed the power button and it booted! weird sh!*.

Android stuck in Bluetooth boot loop

I got used to my Touchpad tablet being so stable and reliable that I was taken aback one day when I turned the Bluetooth on it immediately rebooted,  and rebooted and…..

Yes, the dreaded boot loop had hit my trusty Touchpad.  The Cyanogenmod 9 install had worked (almost) flawlessly for several years. The bluetooth worked well but I never kept it turned on.

I couldn’t believe that Android became useless because of one area of corruption.  I have ClockWorkMod recovery installed but my last backup was a little old.  I tried clearing the cache, then the Dalvik cache but neither made any difference.

I wanted to use Safe mode but I don’t think CM9 has one.  I could still boot into WebOS but it has no way to access the root of CM9.  So I thought ADB would be the way forward.  I wanted to erase the /data/misc/bluetoothd path contents, but CWM v5 doesn’t give you ADB access.

So I eventually entered the world of Edify, the Android updater script. I found it a struggle to understand but came across the “Android Script Creator” for Windows and I was able to create a script that deleted the contents of /data/misc/bluetoothd.

I have made this fix available if anyone finds themselves in this predicament.

  1. Boot into CWM recovery and connect a USB cable to your PC.
  2. Select mount USB storage in CWM, PC sees it as a drive.
  3. Copy BTreset.zip to the Android SD.
  4. Select ‘install zip from sdcard‘ and browse to BTreset.zip.

[downbyid id=’102′  label=’BTreset’ ]

Halogen Oven Woes

Great aren’t they, these halogen ovens. You buy one because its cheap and before you know it your using it for all sorts of things.

 

Then the bulb blows

Ok, not so bad, £15 or so on sethe-bay, but to fit it you have to literally disassemble it. But when its in, it works!

Then it keeps tripping the power

After replacing the bulb I thought that would be it for another 12 months but no, after a couple of weeks it started tripping the house mains power.

Took it apart, thought it was my wiring couldn’t see anything wrong. Wrapped another layer of electrical insulation round the wires put it back together, it worked.

Three weeks later it started shorting out again, aaaarrggh.  Now I’m losing patience with it.  I leave it sitting in the corner of the kitchen sulking, or maybe I was sulking.

Eventually when I was in a better mood I put my voltmeter across the live and earth terminal on the mains plug and yes, it was shorting. Took it apart AGAIN.  I kept the meter on the plug and as I was disassembling the oven it would be shorting then not.  Something like a bare cable I thought was touching the metal bodywork.  But inspecting the cables nothing was amiss.

Thermostat is the Problem

Took the leads of the thermostat and the problem was gone. Hmmm.  I put the voltmeter directly on the thermostat and yes the mains connectors were shorting with the earth side.  Nothing to take apart so I gave it a good soaking with Cillit Bang to degrease it. Hour later dried it off and the short was gone!