Reflowing a laptop PCB ?

(I have zero experience with reflow soldering).

IMHO that means you will need to practice and destroy a lot of motherboards before you start getting things right. This really isn't the kind of thing you should be trying at home unless you have a lot of money to spend on the right equipment..

Try googling "reflowing BGA's". You will find some claims of success here, though probably not many admissions that the fix only lasted a few days. Mostly you will get total failures, I did. I would guess that the ratio of reported sucesses to reported failures is quite large

Good luck.

Gareth.

If there is any hope of the board working again, this would mostlikely exterminate all hope. There are many factors of the sudden death syndrome. some could be solder and tin whisker related.. However, with the heating and cooling cycles of laptops, delaminated contacts and broken traces on the inner layers of the board would seem morelikely. Reflow won't help those situations. Heating can cause solder to move away from the contact points. If you've ever seen some of the early 90 model TVs, a lot of the picture problems I found on those sets was witht the CRT socket solder connections. Crt heats up, melts the solder, solder moves away from the pad and creates gaps between the pin and pad.

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What make & model laptop? HP by any chance?

Find a company with the equipment to remove and replace BGA packages. They will have to be replaced with new chips though.

Here is a description of a rework station ...

and a UK company who offers a service (but not in the laptop field)

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Adrian C

I would first look at the CPU heat sink. Make sure the fan is clean and working properly, and there is heatsink compound under it. The might be a "pad" which is heatsink material also Frank

Also look for 'bad caps' as well, come to think of it.

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Adrian C

689 degrees Fahrenheit to bake surface mounts in convection oven. Duration depends on the size of the SMD. 495 degrees Fahrenheit for solder flow on through the board connections.

These examples are used in the construction of CPU chips.

Doesn't a motherboard contain various plastic items? Connectors, SIMM sockets etc? I shudder to think what would happen to my laptop should I do the above.

Gareth.

I didn't suggest doing anything and gave an explicit example.

However feel free to bake your laptop PCB at 689F and see if I give a f*ck.

Yes you did, indirectly. The question was recommendations for reflowing the PCB, airgun or oven. Your reply was 689F in an oven. You did not clarify that you were answering a different question.

Gareth.

And your opinion of the EU Commission is ?

Graham

Thanks for all the advice. You have convinced me not to rush the whole thing into the kitchen oven :)

To answer some of your questions:

Yes, the PCB has plenty of plastic parts. But I assume it was assembled in a reflow oven, and therefore there must be a safe temperature range (hence my posting here).

The laptop is a subnotebook from a major manufacturer. No need to put a black mark on a specific one - I have read reports of spontaneous shutdowns affecting HP, Dell, Toshiba, etc. It is a Pentium M with i801/i855 chipset.

The failure scenario probably involves mechanical stress and vibrations. As long as I do not type on the internal keyboard or tap on the PCB, the laptop is quite reliable; unfortunately I still cannot locate any specific faulty component. On the other hand, I would expect a cracked pad to cause the laptop to hang rather than shutdown. Or maybe these chipsets are designed to shutdown when ECC-like errors occur ?

I have seen my share of leaking electrolytic caps, but this board has only SMT capacitors. Is it possible to visually recognize a blown one ?

AC