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820-2915 GPU replacement

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ielectron

Member
I got 2 new gpu chips from Duke, 0005, with 1125 date code, i sent a message about this to him but he did not reply so im asking here. We replaced 2 gpu chips, in both case only the gpu is only issue (gpu was reflowed before replacement, and that fixed it), so in both cases what is happening is: after we installed the new GPU chips both laptops turns on with chime, apple logo appears with the loading bar, there is no discoloration or anything which would indicate bad gpu at that point, the loading bar goes up as normal than before it is reaching the end and OSX should load it just restarts. This is the case exactly in both laptops. We figured maybe we did something wring during the new GPU installation, so we reballed the original GPU with leaded balls, installed it back and the laptop works fine, so i guess it is not our method of replacing the GPU.
One of the original GPU was 0005 and replaced with a new 0005, but the second one was 216-0810084, but they show exactly the same issue after replacement.

I found something about installing a resistor depending on the size of the VRAM, but on other forums i found that they replaced the 0084 without modification succesfully with a new 0005.

So at the moment it looks like the chips are bad, but i guess Duke knows very well how to source a good GPU, so i dont know, maybe we are missing something.....
btw... one GPU we reballed with leaded solder to avoid high heat (maxc heat was about 195 Celsius), but the second gpu we just left the original unleaded balls on it (max temp was 228 celsius).

Any idea what am i missing?
 
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I

ielectron

Member
in the meantime, some 0005 chips arrived from china, we did not try them yet, in the coming days we will try them, its just from a random aliexpress seller who has very high feedback, 0005 chips, date 1707
 
D

dukefawks

Administrator
Those chips are fine I use them every day. What boards are these, 2.2/2.3/2.4/2.5??
Oh those Ali chips can go straight in the bin of course.
 
I

ielectron

Member
u mean the cpu freq? that is 2.2

Processor
CPU speed: - 2.2 GHz
CPU Type: - Intel Core i7 (Sandy Bridge)
CPU Model: - 2675QM
Cores: - 4
Bus Speed: - 1333 Mhz
Cache: - 6 MB L3 cache
64-bit: - Yes
Turbo Boost: - Up to 3.3 GHz
 
D

dukefawks

Administrator
Then you have the correct chip. So either bad soldering or you did not remove the glue from the VRAM, dead VRAM, cracked traces.

The one with the 0084 GPU needs a 0810001 chip. If you want to use 0005 you need to change the strapping resistors, R8613 and friend. Compare to identical board, VRAM capacity and vendor.
 
I

ielectron

Member
VRAM glue removed, chips are reflowed , now working.

Do you remove the VRAM glue all the time when replacing the GPU? I tried to refow the GPU many times before, and i never removed the glue from the VRAM with a high success rate, anyway if had to be removed thats alright.

BTW, the chinese 0005 1707 chips is working fine (after reball), but u can see that they are used chips, well, lets see how long would they would, worst case we replace the GPU again with your chips.
 
I

ielectron

Member
Do you, or anyone, have like a list or small database about that resistor configuration, there is 3 different kinda sizes of VRAM, 512MB, 1GB, 2GB, and 2-3 vendors? there many options, we dont have all the boards to compare.
 
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dukefawks

Administrator
Please just source the correct chips as not all combinations work and the diagram is missing half of them.
The Chinese fake chips will last anywhere from 3-9 months, so be fair and give a 1 year warranty on this stuff!
 
I

ielectron

Member
so you are saying that if we have only the 0005 chips we wont be able to fix every 820-2915 boards? would it be better to stock the 0001 as well? so far with gpu issue we only got the 2915 boards and nothing else.

So a 2915 board must be fixable with either with 0005 or 0001 chips? is there any other kinda gpu needed for those board?
 
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dukefawks

Administrator
You need 0810005, 0810001 and 0809000. Most of them are not available and anything on Ebay and Ali is fake. Only one you can sort of trust is SEE-IC on Ebay and specifically ask for NEW chips.
 
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