First reflow please advise

[zulux]

Hello there,I am going to attempt a reflow of the graphic chip on a HP Pavillion dv9000,I have everything I need and I'm not expecting great results but my question is-how long do I keep the heatgun on the chip?I have seen you tube videos that range from 4minutes-10minutes! I would like to just do this once as my biggest worry is disassembly and reassembly of the laptop.I will be so very grateful for a definitive answer to this,could I add secondly-Is it not wise to add copper shims?some tutorials add shims and others say definitley not,I have two shims but I am not sure now if they should be used.many thanks.

 

[dish_moose]

There is no good answer unless you had a temperature controlled reflow station. Semiconductors can take an amazing amount of heat. What are you using to heat the IC/board? Also are there components on the bottom? If you heat it to much components will drop off the bottom side. I would recommend placing something with some give to it yet able to withstand some heat on the bottom of the board. Also if the air is blowing too hard you can blow components off the top side as the solder melts. Best answer - look for signs of solder melting and go an additional 2-3 min - if that doesn't work - go a couple longer next time - you have nothing to loose.
-Bruce
BTW I do some SMT rework and pcb assembly as part of my job.
-Bruce

 

[zulux]

Thank you dish_moose,I will be using a Black and Decker paint stripper and I will remove the mobo and be placing multiple layers of silver foil over that,..how will I see signs of solder melting if I have the board covered?should I leave some of the board exposed? thank you for your time

 

[smorizio]

before you do that is your laptop part of the nvidia gpu recall if it is there still and is a big class action lawsuit agaist hp and nvidia. hp in the action was going to replace the laptops for free.

 

[flank21]

hey zulux I have a dv9740us and I had an issue with graphics artifacts all over my screen and then the "nvidia driver stop responding error" My laptop has a nvidia 8600m, and I disassembled it for the first time and to my amazement I found 0 traces of thermal paste on the gpu and gpu heatsink (a little upsetting) I was luckily able to track down my issue to the vram. I heat gunned my vram chips for ~5 mins. My hp laptop has a separate heatsink for the gpu and it had those stupid thermal pads on the vram to fill the gap and make contact with the gpu heatsink. So the only thing I ended up shimming was the 4 vram chips and I did this by cutting the "fins" from an old heatsink and affixing them to my gpu heatsink with thermal adhesive. Granted you may have a model with a different gpu and shared memory, my model had a discrete gpu and dedicated vram.

I covered everything except the parts I was going to heat gun and then once finished DO NOT MOVE IT for at least 30 mins.

 

[zulux]

before you do that is your laptop part of the nvidia gpu recall if it is there still and is a big class action lawsuit agaist hp and nvidia. hp in the action was going to replace the laptops for free.

I read that ,that class action lawsuit was over now and I was too late?

 

[zulux]

hey zulux I have a dv9740us and I had an issue with graphics artifacts all over my screen and then the "nvidia driver stop responding error" My laptop has a nvidia 8600m, and I disassembled it for the first time and to my amazement I found 0 traces of thermal paste on the gpu and gpu heatsink (a little upsetting) I was luckily able to track down my issue to the vram. I heat gunned my vram chips for ~5 mins. My hp laptop has a separate heatsink for the gpu and it had those stupid thermal pads on the vram to fill the gap and make contact with the gpu heatsink. So the only thing I ended up shimming was the 4 vram chips and I did this by cutting the "fins" from an old heatsink and affixing them to my gpu heatsink with thermal adhesive. Granted you may have a model with a different gpu and shared memory, my model had a discrete gpu and dedicated vram.

I covered everything except the parts I was going to heat gun and then once finished DO NOT MOVE IT for at least 30 mins.

Apparently HP did not use thermal paste with the dv9000 just thermal pads,thaks for your reply I will bear in mind what you have said thank you