Advice on reflowing HP DV6000?

[JGAN]

Hi everyone,
I have a HP DV810US (subset of DV6700, subset of DV6000) laptop that has a "no power" symptom most likely caused by a bad NVIDIA chip. I'm looking to reflow the chipset with either a butane pencil torch/heat gun or oven. Is one method "safer" than the other? I would prefer the torch method if there is no reason not to.

Also, how should I go about doing this? There are so many different methods online, each more absurd than before :/ Basically, if I use a butane torch, I'm going to also have an IR thermometer to monitor the temps and make sure it doesn't get over 250ºC. My idea is just to heat it up slowly from above, about 10ºC-20ºC/minute. I will also have added petroleum-based rosin flux beforehand.

However, some people say that you should set the motherboard at a 45º angle. In addition, they instruct you to heat it up from the bottom first, and then flip it over to the top and finish reflowing there. Others even go as far as saying that you should apply some pressure to the chip when you are reflowing it.

Who is correct here? What advice should I take in order to get the best possible results?

Thanks,
JGAN

[Th3_uN1Qu3]

Re: Advice on reflowing HP DV6000?

Add flux around the sides of the chip then heat the board lightly from the bottom first, right under the chip, till the top of the chip reaches 140C. This will make the flux go under the chip and clean the solder to some degree (thanks momaka, i previously struggled with pushing the flux in from the top with a thin nozzle on my hot air gun). Then flip it over and heat it from the top.

I wouldn't go over 230C. Once you've reached 230C, keep it like that for a minute or so, then slowly back away and let it cool down to lower than 50C before you start re-assembly.

[Joun]

Re: Advice on reflowing HP DV6000?

You're having "no power" or "no video" symptoms?If you have "no power" I don't think it will work,it could be many other things.

P.S Whatever you do don't EVER apply preasure on chip while reflowing it.This will squash the solder balls underneath(they're more or less liquid remember?) making not contact at all.

[JGAN]

Re: Advice on reflowing HP DV6000?

Thanks for the answers everyone,

You're having "no power" or "no video" symptoms?If you have "no power" I don't think it will work,it could be many other things.

P.S Whatever you do don't EVER apply preasure on chip while reflowing it.This will squash the solder balls underneath(they're more or less liquid remember?) making not contact at all.

I have a "no power" symptom (see here). I checked the coils/inductors, most of the main mosfets, and some caps already. Also, I get 3.35v at the switch, so now I suspect it is the chipset, but I suppose I could be wrong.

[JGAN]

Re: Advice on reflowing HP DV6000?

Add flux around the sides of the chip then heat the board lightly from the bottom first, right under the chip, till the top of the chip reaches 140C. This will make the flux go under the chip and clean the solder to some degree (thanks momaka, i previously struggled with pushing the flux in from the top with a thin nozzle on my hot air gun). Then flip it over and heat it from the top.

I wouldn't go over 230C. Once you've reached 230C, keep it like that for a minute or so, then slowly back away and let it cool down to lower than 50C before you start re-assembly.

Are you sure its not dangerous to move the board when it's hot?

[Th3_uN1Qu3]

Re: Advice on reflowing HP DV6000?

Obviously, let the board cool back down before you flip it.

[JGAN]

Re: Advice on reflowing HP DV6000?

I meant when it's being warmed up from the back?

[Th3_uN1Qu3]

Re: Advice on reflowing HP DV6000?

Yes. Put flux around the GPU, warm the back of the board under the GPU to allow flux to get in, let it cool, then flip it on the other side and heat the GPU from the top.

[JGAN]

Re: Advice on reflowing HP DV6000?

Got it, thanks! Any other tips?

[Th3_uN1Qu3]

Re: Advice on reflowing HP DV6000?

If it has that stupid thermal pad thing on the GPU, replace it with a copper shim with good quality thermal paste on both sides. You can find packs of copper shims on ebay for next to nothing, made specifically for this purpose. But get it up and running first, and then we'll see.

[JGAN]

Re: Advice on reflowing HP DV6000?

Just a quick question: Do you know how to test the NVIDIA chipset with a multimeter? I want to make sure that is really the problem. Schematic is attached if you would like to see it.

[999999999]

Re: Advice on reflowing HP DV6000?

You can't (reasonably, unless you get extremely lucky) test a chipset with a multimeter.

Keep something in mind. The problem with this series is not just the solder pads under the chipset, it's also the solder balls INSIDE the chip itself. Typically the people lucky enough to get one working again, have another failure within a few months.

IMO, you're better off parting out the system and buying something else even if that means a used system or a barebone with which you reuse some parts like HDD, memory, CPU - but one with a different chipset.

[b700029]

Re: Advice on reflowing HP DV6000?

Just a quick question: Do you know how to test the NVIDIA chipset with a multimeter? I want to make sure that is really the problem. Schematic is attached if you would like to see it.

A multimeter won't work. You might even damage it with the ohmmeter bias voltage, since these chips are not designed to take much more than ~1v. Either way it'll show as shorted across the power rails, just like a CPU, because it's a high current low voltage device.

[momaka]

Re: Advice on reflowing HP DV6000?

P.S Whatever you do don't EVER apply preasure on chip while reflowing it.This will squash the solder balls underneath(they're more or less liquid remember?) making not contact at all.

+1

I've done that as an experiment on a few Xbox 360s. It's very easy to move the chip sideways and bridge the balls underneath so don't do it. You can also squish them too hard and cause them to bridge.

However, you CAN very very gently nudge the chip sideways with tweezers to check if the solder underneath it has melted. If it has, it would be very easy to nudge the chip without having to apply any pressure at all, and the chip should move right back into its place where it was.
Keep in mind that if you're not careful or if you have shaky hands, you could potentially nudge the chip too far and bridge some of the solder balls underneath it. For this reason, I HIGHLY recommend people new to reflowing to NOT try it.

thanks momaka, i previously struggled with pushing the flux in from the top with a thin nozzle on my hot air gun

Glad I could be of any help.

[JGAN]

Re: Advice on reflowing HP DV6000?

Ok, I think I should be able to tell when the solder has melted with the theremometer.

What sort of motion should I move in?

Thanks everyone for the help so far! I really appreciate it

[smason]

Re: Advice on reflowing HP DV6000?

Ok, I think I should be able to tell when the solder has melted with the theremometer.

What sort of motion should I move in?

Thanks everyone for the help so far! I really appreciate it

The last 2 DV6000s I worked on, I moved in the direction of the recyclers.
One of the worst POSes HP ever made.