Re: Macbook A1989 - 820-00850-A Won't turn on - stuck at 5V/5mA
There is nothing. It looks like C7883 is burned.
There is nothing. It looks like C7883 is burned.
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Last edited by martyjelen; 05-16-2023, 06:24 AM. -
Re: Macbook A1989 - 820-00850-A Won't turn on - stuck at 5V/5mA
Remove this capacitor. Test again without this component.Comment
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Re: Macbook A1989 - 820-00850-A Won't turn on - stuck at 5V/5mA
Now the U7800 is not hot anymore. Still 20V / 0.4A. Should I put the PCB back and test it again?Comment
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Re: Macbook A1989 - 820-00850-A Won't turn on - stuck at 5V/5mA
Sure. Not sure what the true current consumption is for a working board but test it to see if you can see the display power on logo.Comment
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Re: Macbook A1989 - 820-00850-A Won't turn on - stuck at 5V/5mA
It works without any problem now. Just doing a time machine backup.
Thank you very much again. Also thanks to piernov.Comment
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Re: Macbook A1989 - 820-00850-A Won't turn on - stuck at 5V/5mA
Excellent. This was a very good case and added to my knowledgebase.Comment
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MacBook PRO A1989 won't turn on
Hello everyone at badcaps,
Today, I have a MacBook Pro A1989 on my workbench that is not powering on. While conducting some tests, I noticed that as soon as I connect the charger, I observed using a thermal camera that the T2 chip begins to heat up, reaching temperatures between 33 and 32 degrees Celsius. I've only measured the input voltages of 12V and 3V at the coil "L7660," but the expected 5V voltage at "L7600" is not present.
I don't have much experience with this type of equipment; my repairs are mostly focused on common laptops like HP, Samsung, etc. This is why I suspect I might be measuring incorrectly.
However, I would appreciate learning at least the basic measurements to see if I can fix this MacBook. Thank you in advance.Attached FilesComment
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Hey guys,
I got a MacBook Pro a1989 820-00850-A dead for repair. The MacBook itself was off for a month or so and it didn't power on. I tested using ammeter and it was stuck on 5v. Opened the machine and found a short on ppbus_g3h, corrosion near the right spkr_amp. removed the spkr_amp and saw short on ppbus_g3h. plugged in to power, boosted to 20v .600A and then back down to .300A. Trackpad was clicking when on .600A but no image etc.
Later, I tried again but it dropped down to 5v and never boosted back to 20V. checked board again and found ppbus_g3h shorted again....10-06-2025, 08:45 AM -
MacBook A1989. does not work with dfu. Stuck in DFU and won't turn on!
20 volts and 0.00 amperes
Does anyone have any suggestions?
It's possible that the problem is in the EFI (BIOS),
who has the EFI ROM file please share -
Hi,
Preface : My primary job it's not repairing logic board, so please excuse me.
The Macbook A1989 is stuck at 5v at 0.3A on three usb-c port, and in one port no absorption, so the incriminated chip may be the CD3125.
I'have read that these mac have two CD3125 in daisy chain.
How can i confirm my diagnose before reballing it? Someone have experience with this issue?... -
Hi,
I have a MacBook Pro 13 inch A2238 M2 and it was stuck 5V with 0 amps. I measured some important lines and I found a short on PP3V8_AON_MPMU_ISNS_VIN, I tried injecting 1v and I saw heat coming from the mPMU so I removed the pmu thinking that was the problem. I don't know why I didn't check the other side of the border but there it was, a shorted cap. I replaced the cap and the short was gone, so I reballed the PMU and put it on again but voltage was still stuck at 5V and the current was fluctuating between 0 and 0.45 amps. I checked under the thermal camera and I saw the mPM...04-02-2025, 05:02 PM -
Dear friends,
a close friend of mine gave me this machine, she told me that the last days the fan was going high and that it was heating up too much for the usual things, and that suddenly one morning it didn't start anymore .
I opened it and inspected carefully with a high magnifying lens, found no oxydized spots but a short on PPBUS_G3H , then a blown U6903.
I changed U6903 with a new one, PPBUS_G3H became 558 (measuring with red probe to gnd , and black on F7000) , PP3V3_G3H_RTC 463.
Now when I plug the usbc cable (original Apple 61W power supply), nothing starts automatically,...
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