Hello All
I was handed a 2018 Mac Mini that will not turn on. The only history that I have with it is that the customer bought it off eBay as not working.
Pressing the power button, nothing happens. I've inspected the board and I don't see any shorts. The power supply is providing the required 12v.
I put the Mini into DFU mode but I find that all of the menu options are greyed out like it's not really communicating. I'm using a TB4 cable which has worked on other computers for DFU.
I haven't seen this before so just curious if anyone has any thoughts....
ACS-Repair
Last Activity: 05-04-2026, 12:08 PM
Joined: 02-13-2021
Location: Pickering Ontario
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I have an A1398 motherboard that is working normally with 1.78v. I know that this board, and other A1398 boards, suffered from failing CPU mosfets. I replaced the original FDMF6808 with FDMF3030. This solved a similar problem that I was having. Other replacements are available as well. You can do a search on this original mosfet part number to find similar examples.... -
Sorry for the delayed response... I just realized that I had a typo, the board is an 820-3662, not 3663 (which doesn't exist). The IC is U5823, which is the same on 820-00138, 820-00163, and 820-00426 boards. it is located right next to the Airport card slot J3501....Leave a comment:
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Just an update... the customer all of a sudden decided that they did not want to repair their computer or do a data recovery. I've given it back and that's the end of it. Thanks for your response mon2.Leave a comment:
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I received a proper Thunderbolt cable and was able to connect to the computer, but I wasn't able to "revive" the computer. I was able to put the computer in Target Disk Mode but I'm waiting on the customer to provide the proper password.
I found that there is a definite backlight problem as well. There is 0v on the PPVOUT_S0_LCDBKLT. If I measure this to ground I get 42 ohms, which I believe means there is a short. I will disconnect the screen to make sure it is not a screen issue, but I see there are a number of faults like this with a shorted capacitor on that line....Leave a comment:
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Just an update...
I was able to put the computer into DFU mode but the "Revive" process kicked out after going only about 50% on step 4 of 4 without reporting any errors.
I'm not sure whether my USB-C cables are good enough so I've order a quality data cable which will arrive tomorrow. I'll try again to see if this works any better....Leave a comment:
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Thanks mon2
I have 2.51v on both PP2V5_NAND_SSD0 and PP2V5_NAND_SSD1. The board is very clean although I have not removed the board yet to check the other side. The customer did not mention any liquid spill
and I am still trying to decide how far I want to go with this due to my lack of experience on this model.
I checked those links but my issue is different.Last edited by ACS-Repair; 02-05-2025, 08:50 AM.Leave a comment:
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MacBook Pro A2141 820-01700 Boot loop
Hello All,
I was handed a 2019 MacBook Pro A2141 that is boot looping. There is never a display or backlight but there is a chime about every 8-10 seconds.
I plugged in a USB-C meter and it see that it is negotiating 20 volts but there is no current draw at all. Voltage is stable, no resets.
It appears that the battery has a charge but possibly is not charging.
The following voltages are present:
PPBUS_G3H = 12.61V
PP3V3_G3H = 3.33V
PP3V3_GH3HRTC = 3.33
I haven't worked n one of these before so I have limited experience with... -
This new version is fantastic. I can't believe that you added the window box to the free version as well. You are the man Paul !!Leave a comment:
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Wow! Good work resolving the issue....Leave a comment:
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It looks to me that the screen is damaged. I had a screen like this that would have a shimmering effect on some colours and brightness levels. Do you have another screen to try?...Leave a comment:
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820-00165 USB2 but no USB3 from LIO board
I've been working on an 820-00165 parts board that would read USB2 flash drives from the LIO board but not USB3. The issue was not the LIO board, confirmed after swapping it. I didn't realize this was a even a possibility but I discovered that the signal USB3_EXTB_R2D_P was not getting through. I noticed that once again a component, C9521, was missing on the board. Once I replaced this capacitor the board would read both USB2 and USB3 flash drives.
While i was able to resolve this myself, I hope that this helps with the understanding of how this board works.​ -
Hi Paul, this post about recent upgrades seems to be in the future. Is this what you intended? Great work by the way!!Leave a comment:
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So, this is an old post but I have an update that I'd like to share... I connected a camera from a broken screen that I have and the the camera came up right away. it seems that I've been chasing what I thought was a logic board problem but it was a camera fault. I just sold the display to someone so I don't have it here to see what was wrong. I'm going to need to contact the person so I can replace it for them. I thought it very unusual that it was the camera itself that was at fault.Leave a comment:
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Thanks piernov, I may be wrong about the startup order, but in either case, my experience is that this condition is indicative of a dedicated GPU hardware failure, common on this model. This can be brought back temporarilly by a GPU reflow or by using the dosdude1 patch process.
Hopefully, this will help lordhex or anyone in this position to get their MBP back with limited operation. I've done several of these with the dosdude1 procedure and it has worked well.
Another test is to boot with Linux and see if computer completes the startup. I have 2 logic boards now 820-00165 and 820-00138...Leave a comment:
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Sorry this is a bit delayed...
Yes, it is a GPU fault. The transition you see is where it switches from internal to dedicated GPU.
It is possible to bypass the dedicated GPU a couple of different ways. Dosdude1 has a procedure that although lengthy, it does give you back the use of the computer. I have done several of these with success.
Do a search for him where he will outline the process on his website.Leave a comment:
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Re: FlexBV FREE Edition - Modern Boardview software for Win, macOS and Linux
I downloaded this after hearing about it on Graham's channel. Nice work! This is a great effort.Leave a comment:
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Re: Macbook A1466 dies when charger disconnected
I had something like this on an A1398 where the computer showed the battery at 71% but not charging. it also would not run on the battery. in my case the battery was faulty. I agree with mon2... it's best to have another battery to compare with.Leave a comment:
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Re: Alienware Keyboard Not Working In Windows
Although this may not help you much, have you tried loading a Linux Live CD to see if that loads? This would at least get you by the BIOS.Leave a comment:
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Re: MacBook Air 820-00165 Camera Not Detected
OK, I have it back now. one of the resistors that I replaced some time ago (R2281) had rotated 90 degrees cutting off the PP1V2_S3 to PP0V6_S3_MEM_VREFCA_B. Not sure how that happened but it's connected again and the computer comes on.
I loaded an EFI image that piernov provided in an earlier thread and that works great.
I'll need to think about whether to pursue this camera issue or just accept that it's not going to work. I don't like to give up on problems but I don't want to risk anything more with this while it's working....Leave a comment:
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