Tuesday, November 8, 2011
HP Pavilion dv2000 Laptop Troubles
One of the things that I like to do in my spare time is tinker with computer software/hardware. Recently, I came across a product design/implementation that I thought should never have occurred/existed. Perhaps it was a one in a million case but based on my research it wasn't. It was a HP Pavilion dv2000.
Based on what I was told the working system was left in storage (inside a house so thermal/weather issues shouldn't have really been an issue) and hadn't been touched in several months. When it was turned on, all the LED's lit up but the machine didn't seem to 'boot'. There was nothing on either the LCD or an external monitor. Research and intuition thought that it had something to do with the discrete graphics chip (Nvidia) but I couldn't be sure until I had opened/examined the machine.
If you've ever opened up a laptop you've probably figured out that it is a pain and they often have design compromises with regards to accessibilty, cooling issues, and so on. A tip for those who attempt to disassemble this machine, go for the top/middle screws, then attack the left side of the top panel first and then attack the right hand side of the top panel after turning the screen towards you temporarily (you'll understand why if you ever try this). Then remove the keyboard and finally seperate the main shell/panels after removing the relevant screws.
When I finally took a closer look at the graphics chip and the connection to the mainboard I noticed that some 'balls' were completely flattened and obviously could not have been connected to the mainboard. Moreover, some balls ended up being in contact with others. Removal/reshaping of damaged balls was obviously a possibility but as I've previously discovered (and documented in this blog) 're-flowing' is only a temporary solution. A 're-ball' is the only real medium/longer term solution since its an inherent design fault that never should have existed.
Obviously, I tried a re-balled mainboard. However, after re-connecting everything I discovered that the lid switch which is used to detect when to suspend the notebook was dead which led to backlighting issues and is another known design fault with this particular notebook. While a fix is possible longer term it is likely to fail anyhow and the ability to hibernate can still be accessed by using the power button. Research indicates that the 'best solution' is bypassing the problem by merely disconnecting the lid connector to the mainboard.
At the end of all of this I discovered that the power switch wires had come loose. I didn't realise was how fragile something like this was and how difficult it was to solder using a general purpose iron (though I eventually got it). From a practical perspective the wires are too small to strip easily (unless you have specialised equipment). In fact, I used small nail clippers! Thereafter, you'll notice that you must apply a coating over the wires in order for the connection to remain stable after re-assembling the laptop. I tried liquid electrical tape but while it is a good insulator it isn't as strong you would really want. Moreover, there are time issues associated with drying/curing.
Normal tape is possible but I found that it lacked 'adhesive power'. I finally tried, 'industrial strength adhesive tape'. It reminds of 'gaffa tape' but is more pliable making it easier to fit around gaps and wires. Personally, it feels like a cross between liquid adhesives and tapes. Brilliant stuff and but not as thick as 'gaffa tape' which may cause panels to be slightly out of kilter when re-assembling the machine.
Once the laptop was re-assembled you may find that device drivers may need to be updated. I discovered that I needed to manually force the Conexant HD Audio drivers to be used in order for them to work. Windows/software based hardware auto-detection just didn't work.
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