HP Elitebook 8730w Motherboard Charging Circuit Problem

Hey folks,

I've been experiencing random bluescreens and shutdowns in the past few months and was wondering if you guys could help me resolve this issue, which after much thought seems to be caused by some fault in the motherboard battery charging circuit, which could be quite a challenge to repair.

So before going further ahead I would love to hear your take on this.

It all started after I was getting random bluescreens and noticing the computer was getting quite hot, with the occasional shutdown even with the power supply connected, so thinking it was probably caused by dust clogging the cooling fins, I totally dismantled the laptop and cleaned it thoroughly and it went back to running cool again.

However, after a few days the bluescreens returned and yesterday, I experienced yet another shutdown after doing some heavy duty Google Earth 3D rendering for a few hours, even though the computer was correctly connected to the power supply.

Thinking it could simply be a video card issue due to the heavy duty 3D rendering, I restarted the computer and it went back to the desktop as it normally does, but I immediately noticed the battery was down to 0% and was incredibly hot. Thinking it was simply the battery, I put it in the freezer for a few minutes to cool off and installed one of my spares, which turned out to be discharged as well and requiring a recharge.

This is when I noticed that even with this cool battery, it was taking forever to charge, Passmark BatteryMon would indicate a charging rate of only 4000mW, which would require a full night to fully recharge. I can understand that with a hot battery, but why would it do that with one that had been sitting on the shelf for several weeks?

I admit my batteries aren't new, they are a few years old and even if I hardly ever run my machine off of the battery, I was willing to to believe the problem was indeed my batteries.

So thinking that my machine was perhaps just too hot, I took it off the docking station, put it aside, removed the battery, installed the battery in my spare 8730w, dropped that machine into the docking station, started it up and installed Passmark BatteryMon on it.

Lo and behold, the battery that was only trickle charging when installed on my main machine was now registering a healthy charging rate, approximately 10 times that of my main one, for an estimated full recharge of little more than an hour!

We're talking here same battery, same charger and same docking station!

So I shut down my spare 8730w again, removed the battery and reinstalled it into the main laptop which I had put aside and connected it to another charger without turning it on, just to charge the battery, which it appeared to do normally (yellow LED). I then took the now cooled warm battery out of the freezer into the spare 8730w, which I then dropped into the docking station, started and let idle while I prepared myself supper.

After I came back, the originally hot battery in my spare laptop had gone up to over 60% of charge and seemed to keep charging normally, without overheating. I then shut down the spare laptop, removed the battery and installed the one that had been charging in the main laptop while off and after restarting the spare laptop, noticed it had risen to only 20% in the same amount of time that the other battery had risen to 60%. However, after a few minutes charging in the spare laptop, I could see it charging at a rapid rate again.

This lets me believe the problem cannot be the charging jack (since the problem happens whether I use the charging jack or the docking station), the charger (since charging works normally when I install the other laptop in the docking station, whether I use one charger or another one), the docking station (charging works fine with my spare laptop) and the battery (since batteries charge at a normal rate when charging in my other laptop), and I can only come to the conclusion that there is some hardware problem in my main laptop's charging circuit :-(

So I'm asking you guys, does my interpretation make sense, or did I miss something obvious as a possible cause? If my interpretation is correct, do you have any pointers what I should be looking for? And more importantly, is there a practical way to repair a motherboard with such an issue without a complex soldering setup? I am proficient with a soldering iron and can probably replace a jack or something of that size and simplicity, but replacing a multi-legged SMD chip on the motherboard, provided I can actually diagnose the problem component accurately, is quite another story.

Any ideas, thoughts and comments? Don't be shy to let me know what you think!