smiba
New member
I don't even know where to start at this moment anymore, I've been working on this device most of my day and It just doesn't want to work.
Story:
Customer handed me his macbook. Told me he got the motherboard replaced at company *X* for $700 a year ago, but now it keeps rebooting, is unstable or doesn't want to power up at times. He checked and said there was lots of corrosion but company *X* told him it was his fault and not theirs.
After opening up the macbook and inspecting the motherboard it looked like absolutely trash underneath the microscope. Flux everywhere and it just looks like all the parts were resolderd atleast once. On every single part of the board where the pads would usually be nostuff there is solder now, indicating someone went past it with his iron.
They also used this annoying thick flux which is just surrounding most of the chips, its not solid but its definitely hard to remove at room temperature, it also makes it hard for me to probe points.
After some good inspection the most screwed up part was around the SMC, quite the bit of corrosion. I cleaned most of the corrosion up with 99.9% 2-Propanol and checked but it didn't solve the issues (When will it ever be simple? haha), the system was still acting rather oddly and most of the time wouldn't even power on..
I expected corrosion underneath the SMC, since its the logical explanation why power management is acting weird. I de-soldered the SMC and placed on a new one. Well this is where the bigger issues started, now the system always powers on.. But there is no Chime and No display.
Often the system stays on for about 8 seconds before it shuts down completely, if you quickly reconnect the charger it will power on again and stay on (But still no Chime and display).
VCore is 1.15V and the CPU gets warm, if I power it on without any ram modules installed the system would start beeping, indicating an issue with ram.
I then replaced the SMC chip with another new one (You never really know what kind of crap china sends you), however the issue stayed exactly the same.
I also checked the data going in to the SPI Chip (U6100), the CLK is there and it seems like data is both going IN&OUT. The clock and data looks pretty odd compared to a working 820-3115, in the start there is about 1-2 seconds of 0.5 second long high/low pulses before actual data is being sent. Also sometimes these long pulses happen while also data is going over it.
It might not be relatable to this issue, though.
Short Version:
Macbook had issues with booting at times, very unstable. Corrosion on the board and just a lot of flux everywhere from someone else. Cleaned corrosion and decided to replace SMC chip due lots of corrosion around that area. After new SMC the light on the charger shows, the fan spins but there is no Chime and no Display or backlight. Replaced with another SMC chip (from the same batch), same issues.
CPU VCore is 1.15V, CPU gets warm and when booted up without RAM memory it will beep.
System often shuts down after about 8 seconds, but when booted up for the second time in a very short period it will stay on.
Checked U6100 (SPI Chip's clock and data, looked a bit off compared to a 820-3115. I however don't have another 820-2936 to compare.
All major power lines are up as far as I checked
I got a digital oscilloscope, its not state of the art technology but good enough to see clocks and data over non-high speed chips. If you want me to check some part with the oscilloscope I can post screenshots of its output.
Questions:
- Where to look? What could be causing this issue?
- Might the second SMC also be bad? Is it worth a fair try to replace it a 3rd time but with a totally different seller's stock?
- Is it possible I toasted the chipset (U1800) while soldering the SMC back on? (I doubt it, I didn't use /insane/ temperatures. I can't exclude it either though..)
Thanks in advance, let me know if there are any questions.
Story:
Customer handed me his macbook. Told me he got the motherboard replaced at company *X* for $700 a year ago, but now it keeps rebooting, is unstable or doesn't want to power up at times. He checked and said there was lots of corrosion but company *X* told him it was his fault and not theirs.
After opening up the macbook and inspecting the motherboard it looked like absolutely trash underneath the microscope. Flux everywhere and it just looks like all the parts were resolderd atleast once. On every single part of the board where the pads would usually be nostuff there is solder now, indicating someone went past it with his iron.
They also used this annoying thick flux which is just surrounding most of the chips, its not solid but its definitely hard to remove at room temperature, it also makes it hard for me to probe points.
After some good inspection the most screwed up part was around the SMC, quite the bit of corrosion. I cleaned most of the corrosion up with 99.9% 2-Propanol and checked but it didn't solve the issues (When will it ever be simple? haha), the system was still acting rather oddly and most of the time wouldn't even power on..
I expected corrosion underneath the SMC, since its the logical explanation why power management is acting weird. I de-soldered the SMC and placed on a new one. Well this is where the bigger issues started, now the system always powers on.. But there is no Chime and No display.
Often the system stays on for about 8 seconds before it shuts down completely, if you quickly reconnect the charger it will power on again and stay on (But still no Chime and display).
VCore is 1.15V and the CPU gets warm, if I power it on without any ram modules installed the system would start beeping, indicating an issue with ram.
I then replaced the SMC chip with another new one (You never really know what kind of crap china sends you), however the issue stayed exactly the same.
I also checked the data going in to the SPI Chip (U6100), the CLK is there and it seems like data is both going IN&OUT. The clock and data looks pretty odd compared to a working 820-3115, in the start there is about 1-2 seconds of 0.5 second long high/low pulses before actual data is being sent. Also sometimes these long pulses happen while also data is going over it.
It might not be relatable to this issue, though.
Short Version:
Macbook had issues with booting at times, very unstable. Corrosion on the board and just a lot of flux everywhere from someone else. Cleaned corrosion and decided to replace SMC chip due lots of corrosion around that area. After new SMC the light on the charger shows, the fan spins but there is no Chime and no Display or backlight. Replaced with another SMC chip (from the same batch), same issues.
CPU VCore is 1.15V, CPU gets warm and when booted up without RAM memory it will beep.
System often shuts down after about 8 seconds, but when booted up for the second time in a very short period it will stay on.
Checked U6100 (SPI Chip's clock and data, looked a bit off compared to a 820-3115. I however don't have another 820-2936 to compare.
All major power lines are up as far as I checked
I got a digital oscilloscope, its not state of the art technology but good enough to see clocks and data over non-high speed chips. If you want me to check some part with the oscilloscope I can post screenshots of its output.
Questions:
- Where to look? What could be causing this issue?
- Might the second SMC also be bad? Is it worth a fair try to replace it a 3rd time but with a totally different seller's stock?
- Is it possible I toasted the chipset (U1800) while soldering the SMC back on? (I doubt it, I didn't use /insane/ temperatures. I can't exclude it either though..)
Thanks in advance, let me know if there are any questions.
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