November 7, 2014
Failure is caused by degradation of solder over time. Degraded solder can sometimes break leaving a gap in connection. To repair a broken connection solder must be melted so the two sides of broken connection join again. The process is called reflowing. The affected component must be unsoldered, and solder the component back again. Without proper equipment, this can be very hard to do with components like GPU.
My mom's laptop computer wouldn't power on, caps lock light blinks 5 times indicating "General system board failure". It's is a lower end market laptop computer, a HP Compaq 615, and this type of failure is common for that model. But luckily it can be repaired using a little unorthodox method - by baking a motherboard in an oven.
Simpler way of doing a reflow is heating up the whole motherboard in an oven. This is not a permanent solution, as I am doing this for the 3rd time in last 2 years for the given laptop. The computer lasted a year after every reflow before it needed a reflow again.
First you have to dissasamble the computer and take out the motherboard. Make sure to remember or write down where every screw was, to be able to put it back in the right position as there can be different sizes and with different threads.
When the motherboard is out you have to strip it completely from everything. Remove heatsink, CPU, RAM memory, WiFi module, modem, battery, protective plastic stickers, paper stickers, all plastic parts and everything else that can be removed from the board without braking it off.
To be able to put the motherboard into oven so it doesn't touch anything, I put 3 longer 3mm screws through mounting holes and fix them with nuts to create a tripod. Make sure that the majority of soldered parts is facing up, so they don't fall off when the solder melts.
Before putting the motherboard inside an oven, plan how you will take it out, remember, it will be hot. If you plan to use pliers or something similar to grab the motherboard, then find a place where you will grab it, and put it in an oven in such orientation that this part of board is reachable. It has to be a part of PCB that doesn't contain any components, solder will be melted so touching a component can break it off the board. Also you can put the board on an baking tray and take out the whole baking tray when done. Or you can just leave the board in an oven until everything cools down. I use pliers and take out the board out the oven.
Before putting in the motherboard, preheat the oven to a 180-200 degrees Celsius. That is a melting temperature of a solder. On my oven this is a number 5 on the dial. Put the motherboard in an oven for 8-12 minutes. When done, switch off oven and leav a motherboard to cool down. When it's cold, you can assamble the computer.
A quick test before final assembly shows the computer is functional again.
Thank you for reading.