D620 Isolated Chip Burnout

I'm both skeptical and curious. A good friend of mine suggested that when he walked into his living room one day, he smelled a nasty electronic odor. He came to realize that his wife left the laptop running underneath a comforter on the couch on a rather hot and steamy Rhode Island summer afternoon.

I currently have the laptop. I deciphered that the board is likely garbage right off the bat, because the wireless catch switch has no LED indicator when the laptop is plugged in. The battery also fails to charge and no power indicators, beep codes or "LOCK" indicators above the keyboard show any sign of life when the power button is pushed. I tried multiple power adapters with the proper power ratings. Reseated the CPU, CMOS battery and memory. What probably didn't help the issue was the fact that the heat sink and blower assembly literally mimicked the appearance of a lint trap in a dryer after drying a load of towels. It literally peeled off with ease, it was so dense.

So where am I going with all of this...well, I expected to find the NB die purple (as it also contains the IGP and a VERY poor heating pad solution), but was amazed that it's still as shiny as a mirror. The processor appears to be fine as well, so it's been cleaned up and stored away for now.

The last thing I expected was to find a lonesome, tiny, isolated chip with a giant divet followed by a trail of brown residual matter and damaged solder prongs leading to the board. Notice how in the picture (far left, taken off center to show how lonesome it is), there are four metal standoffs - these actually flex, so I expected that the chasis is designed to have the board "flex" down onto a thermal pad when it's screwed in. I fail to see any evidence of a thermal pad where this chip would push up against. The laptop was a refurb from a couple years ago, so I expected to find out that maybe the technician just ripped it off, but from other photos I have seen on ebay selling panels for parts, I see no evidence of thermal pads.

This board is the econo model, so all it has is an IGP - it doesn't have the Quadro 110m with the additional second heatpipe. I'm actually quite worried that if I purchase another board, the same component is bound to fail in a couple of years. The folks that I am fixing this for hang onto PC's as LONG as they can, so longevity is a major factor. Is it plausible that the heat simply pocketed in JUST the right spot, causing it to fail even before the CPU and NB/IGP?

 

Firstly, the laptop was never intended to be operated in that manner. Not anywhere close. Based on what you say, the ambient temperature alone was probably close to the limit of the design operating temperature. It's not unreasonable to assume that a computer would be tested to above the "normal" operating temperature, but you can be sure that the combination of the fan and heatsink being filled with lint (probably from the comforter) and then it being left turned on a couch and underneath the comforter resulted in the laptop operating well outside the temperature range it was designed for.

Secondly, just because only that particular chip is visibly damaged, does not mean other chips aren't damaged. There is a good chance that chip failed because of a failure elsewhere on the board. However, it could also be that the chip is the "weak link". Even if that's the case, just because it failed in an extreme situation such as this, does not necessarily mean it's prone to fail if the computer is not mis-treated. You could replace the MB, try the same experiment and get the same result, but that does not mean there is something inherently wrong with the chip. (If the laptop almost catches fire when you operate it under a comforter, don't operate under a comforter.)

Your friends should be very relieved the laptop didn't catch fire and burn their house down and they only have to decide whether to take the chance the laptop can be repaired for less than it would cost to just replace it. Please do them a favour and remind them how fortunate they are to still have their home.

 

Yah I agree. Lucky indeed!!! I would kill my gf if she did that.. Just dangerous. Good luck with the repairs though. I think I would be ambitious and try and repair the chip.. of course not expecting success just an adventure that might lead to success.

 

The problem here should be pretty obvious...clogged heatsink. If the heat gets trapped inside, temperatures can rise dramatically. Typically, CPU's are rated to higher temperatures than other chips, so it's not surprising that the heat caused something else to fail.

I would give the heatsink a good cleaning, replace the fan if it is too dusty to be cleaned, replace the motherboard, replace the thermal pad, and replace the thermal grease. Advise your friend's wife to always use the laptop on a smooth and clean surface, and make sure they get a can of compressed air to clean out the heatsink about once a month (or more, depending on air quality).

 

I appreciate all of your time and responses so very much. I was just very curious about how out of all of the components, a rather passive looking component succumbed to heat damage earlier than the usual suspects, on the other side of the board a quarter inch away from the SB. I wouldn't mind trying my hand at soldering a board component; I've had good luck in the past, but there appears to be damage on the PCB unfortunately. Luckily, $65 will get a used motherboard - but who knows how it was used by the prior owner. Oh well, their dime and loss I guess, for buying refurbed laptops from shady, uncaring ebay power sellers.

They also have a D610 which I actually just cleaned out recently - it was FAR worse and was running at over 92C under load according to the die sensor in an air conditioned room. I had to service it after it was dropped and succumbed to a hard drive failure as a result. Applied some AS5, lapped the CPU/GPU blocks and cleaned the heatsink and now it sticks near 80C in a much warmer room under load. The D610 cooling is so much better than the D620, though still mediocre. I wish people took better care of their stuff.

 

If you can pick up a used MB for only $65, that is definitely the way to go. Soldering ICs without the correct equipment is asking for trouble.

Like you say, it comes down to how people take care of their equipment. I frequently use my compressor on all of my computers. I'm careful to keep the laptop off the carpet, but even then, it is amazing how much dust blows out when I use the compressor.

If your friends don't understand how lucky they are, remind them again to never set a running laptop down except on a hard surface such as a tabletop and to never cover it up. (Maybe remind them how lucky they are to have a friend who repairs their mistreated computers.