Re: Compaq Presario F700 cycles on & off
Hello computernerd62 and welome to TSF,
The most likely cause for the issue is the GPU. The F700 was one of many laptops affected by GPU issues. Basically what was happening was, the GPU would heat up and cause the solder that connects it to the motherboard to soften. Over time, repeated heating and cooling cycles, along with electromigration cause bad solder joints between the motherboard and the GPU.
The heating of the GPU, as you stated, is a way to attempt to "re-flow" the solder and restore the connection. This method is usually combined with steps to increase cooling to try and prolong the "fix".
The proper way to fix this issue is to have a professional with the proper equipment, remove the GPU from the board, clean and prep both surfaces, replace the solder with a higher quality solder and then use IR to reattach the GPU to the board. A BGA rework is expensive, and IMHO not worth it.
A home "reflow", when successful can prolong the useful life of the computer by a few months, but the issue will eventually re-occur.
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