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02-06-2023, 03:14 PM
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#1 |
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Meow Meow MEOW!
Join Date: Apr 2020
City & State: USA 🇺🇸
My Country: United States
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A1990 MacBook Pro boot looping
Did a T2 restore. Boot loops constantly then eventually loads the OS.
Did a T2 Restore and revive and OS reinstall. Same issue. Downgraded OS as well nothing. No visible water damage seen. No burn chips and MacBook has never been worked on. Once the OS is fully loaded seems good. For a while. No kernel panic info shows up so definitely curious what’s going on. It does boot fully into safe mode without issue.
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02-06-2023, 03:43 PM
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#2 |
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Badcaps Veteran
Join Date: Dec 2019
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Re: A1990 MacBook Pro boot looping
Check each and every SMBUS line.
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02-07-2023, 04:15 AM
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#3 |
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Member
Join Date: Mar 2022
City & State: 广东省广州市
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Re: A1990 MacBook Pro boot looping
205/2000
Good News and bad news! This kind of problem in my past maintenance experience, encountered a lot of similar models of similar failures, are a problem, CPU bad, BAD CPU! BGA CPU replacement perfect solution! If the appearance of the test, no problem, other measurements, are redundant! |
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02-07-2023, 05:28 AM
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#4 |
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Badcaps Veteran
Join Date: Dec 2019
City & State: Windsor, Ontario
My Country: Canada
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Posts: 6,848
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Re: A1990 MacBook Pro boot looping
Good to know. From where do you source a replacement CPU? Donor board or can you share the details of a good vendor with reballed CPUs?
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02-07-2023, 08:30 PM
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#5 |
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Member
Join Date: Mar 2022
City & State: 广东省广州市
My Country: 中国
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Re: A1990 MacBook Pro boot looping
We generally recycle chips from customers who scrap their motherboards, but we also get them from our peers. Buying them online requires a certain element of luck, which involves, sellers and buyers, IC dismantling, manual problems, and temperature control, if you don't handle it well, it will break!
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02-07-2023, 08:44 PM
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#6 |
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Meow Meow MEOW!
Join Date: Apr 2020
City & State: USA 🇺🇸
My Country: United States
Line Voltage: 120VAC 60hz
I'm a: Hardcore Geek
Posts: 468
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Re: A1990 MacBook Pro boot looping
Sigh it’s a i9 32GB board. Sucks this is a bad CPU or GPU.
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02-08-2023, 01:54 AM
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#7 |
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Member
Join Date: Mar 2022
City & State: 广东省广州市
My Country: 中国
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Re: A1990 MacBook Pro boot looping
There is another solution to this problem, which is to modify the circuitry, to solve the reboot problem, but the researchers have not yet published this solution, and friends around me have learned that it is partially solved by modifying the temperature control, you can go into safe mode, view the system error log, find the corresponding point to modify the circuit! You can try... !
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