820-2915-B GPU replacement failed.

MaxFix

Member
Hi There,

I hope someone can help me with my video problem on MBP 15" 2010. If you look at the pictures the image distortion is exactly as it was before the GPU replacement, which makes me assume that it was not a GPU. But first a little background of the GPU replacement process.

We bought this beautiful BGA machine couple of weeks ago, ZX-D3 from a reputable Dutch SMD tools supplier. I think its Zhou Xiaobo brand or something. Btw that little lightsaber in the middle of hot air gun is a digital microscope that we decided to use for alignment of the cheap, since this model does not have auto alignment, which was 3k more expensive then this 3k machine. Basically we hook it up to computer and put an overlay of diagonal lines on the image that go from the center pad of the GPU on the MB to the four corners and when we put the new chip on it we align it according to these lines. Takes a long time to get the overlay lines exactly right but it seems to work for now.

1. First question is: can you recommend a better alignment technique (faster and simplier). Maybe draw the square around the chip with super paint that doesnt get removed with hot temp and alcohol or maybe something else?

We tested the machine in action with Luios profile from his ZM-R6200 on the test board and it worked like a charm.

After that we have managed to successfully replace 2 iMac GPUs (L2009 and E2011). Tested with ASD - PASSED - better then new! Btw, iMac GPUs are nice to replace because they have this white outline around the chip and do not need expensive alignment machine.

So charged with confidence and positive energy after these two successful GPU replacements, I went on to replace this MBP 15” 2010 GPU but it failed. Because of excitement or my forgetfulness I did not do a diagnostics reflow on this machine to make sure it was the GPU. Well lesson learned hard. But the fuck up doesnt end there and during the removal of underfill from the chip my bamboo stick went a little bit toooooo far and took couple of capacitors with it (C8474 and his big brother C8456). But no biggy, I resoldered them back. How successful? I dont know. These capacitors are still a little mystery to me.

2. Sorry for a lame question but how do I know for certain the capacitor is working correctly on the board? Do I measure AC current or do I do it in a diode mode?

3. Main question. Is it improper GPU installation? Or it is not the problem with GPU but maybe with infamous capacitor? Or smth else?

Thank you for your input.

Max
 

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dukefawks

Administrator
My question is why did you not take this to Apple for a free fix? Clean this up and put it back together and take it to Apple.
 

MaxFix

Member
Good question Duke. Actually its a funny story. Random guy walks into our shop and just hands over his macbook and says:"this shit is fucked, I dont want to fix it, you can have it for spares". He had his hdd, ram and battery removed but for the rest of it, it seems to be in working condition. So I was thinking of fixing his mobo, putting ssd and new battery and reselling this shit. But now that you are telling me that Apple does it for free I will pay them a visit tomorrow! Btw, do I need a proof of purchase (receipt) or I can just say I got it from a friend or smth?
If that doesnt work out and if I would continue with my repair, where do you think I went wrong about it? To make sure same mistake doesnt happen again in the future?

Thanks.
 

dukefawks

Administrator
You don't need anything, just take it to Apple. Make sure you clean up the mess you made with flux.

I have no idea what you did wrong. If this is your first rework chances that it is successful is low. I always reball the new chips with leaded balls. You first need practice on garbage boards, not on machines that are worth 500+.
 

MaxFix

Member
Alright. Thanks for the tip Duke. Practice makes the master. The first two imac video card chips went brilliantly though. Maybe just a beginners luck ;)
You put leaded balls to make sure they all balls melt during rework process? You think there is a chance some of the non leaded balls will not melt onto the pads on the board? I had this doubt too.
Any advice on alignment technique? Or you trust your eagle eye?
 

dukefawks

Administrator
Leaded is just to lower the temperature to lower chances of damage to GPU or other components. I align by eye, if there are no markings on the board I carefully scratch some marks.
 

ALB-Repairs

Member
Regardless of what duke says, The reason it has artifacts is probably the GMUX or VRAM. Especaily if the symtoms are the same.

You may have underfuill in the solder under the VRAM or GMUX. I would reball GMUX then VRAM, Do not reflow these chips, the underfill almost always messes with solder.

As for Leaded VS lead free, ive messed around with both and it really depends on your machine and profile, I had issues with lead free on my shuttlestar, but have no issues on my 2 zone station. With 2915's flex during rework is the biggest issue. im currently fitting them lead free, i think its a better solution.
 

MaxFix

Member
Thanks for your input ALB-Repairs. That macbook is not with us anymore but im sure I will run into the same problem again in the future.
 

MaxFix

Member
I have another troublesome 2915 board with video problems. Came in with no image.

1. Diagnostics reflow. Image is back. (Should have stopped there).
2. Replaced GPU chip. Artifacts on the screen straight from start up. When Video drivers are loaded goes to white screen.
3. Reballed and repositioned GPU chip (just to be sure). Less artifacts on the screen but still white screen after loading video drivers.
4. Tried to reball GMUX but do not have the right stencil out of 222 in my universal stencil kit. STUCK. Anyone knows what stencil I can use for GMUX?

Thanks!
 

dukefawks

Administrator
Why why why did you touch the MUX, it will never cause artifacts and hang the system. I Use universal stencil 0.3mm holes and 0.5mm pitch.
 
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