I’m looking for a board-level diagnosis for my MacBook Pro Retina 15” Mid 2015 (A1398).

Configuration

• Intel Core i7
• 16 GB RAM
• macOS Monterey 12.7.6

History

Before repair:

• The original internal display was cracked but still displayed an image.
• The Mac worked perfectly with an external HDMI monitor.

During repair:

• A technician installed a display from a MacBook Pro 2013.
• The replacement display never worked.
• He reinstalled my original cracked display.
• Since then, the internal display has been completely black.

Current behavior

If the internal display cable is disconnected:

• Apple logo appears on the external HDMI monitor.
• Startup Manager (Option key) works.
• Internet Recovery works.
• But when booting from Macintosh HD, Recovery, EFI Boot or a bootable USB, the Apple logo appears, then the screen goes completely black.

If the internal display cable is connected:

• The internal display remains completely black.

The Mac appears to continue running:

• keyboard backlight works,
• volume keys work,
• fans operate normally,
• but there is no video output.

Already tried

• NVRAM reset
• SMC reset
• Safe Mode
• Internet Recovery
• Bootable USB installer
• OpenCore Legacy Patcher

Always the same result:
Apple logo → black screen.

Verbose mode also showed messages including:

• device is not readable
• failed to initialize volume keybag

Questions

1. Could installing a 2013 Retina display on a 2015 A1398 have damaged the LCD connector or another logic board component?
2. Which is the most likely cause?
   • LCD connector
   • LCD power/backlight circuit
   • Display cable
   • GPU
   • SSD/APFS
   • Logic board
3. What measurements or board-level tests would you perform before replacing parts?

Any advice would be greatly appreciated. Thank you.

⟐ Commented July 23, 2026 at 13:03 MST

This is how it looks

⟐ Commented July 06, 2026 at 13:05 MST

video of issue

Screen

Display cables

Or logic board issues

⟐ Commented July 06, 2026 at 9:02 MST

When switched on, the display shows vertical coloured bars under which the desktop is partially "readable". The MacBook is virtually uncontrollable. The LCD has no visible external damage (only the black rubber around the display is torn in a few places).

The display is probably not the cause of the problem, as the streaks also show up on the external display (another MacBook with the same configuration) as well as on the 9th gen iPad.

What is causing this problem? Is it the LCD cables, connectors, or part of the logic board (the whole board)?

Thank you in advance for your answers.

⟐ Commented June 03, 2026 at 19:24 MST

Basically, is my Anti-glare coating worth removing and if it is, which method is least likely to cause damage? Also, is image quality affected other than the anti glare properties if I were to remove the coating? Like a loss in color accuracy or something like that.

UPDATE

I used some Kirkland signature baby wipes to remove the layer but it was taking forever. I used Clorox wipes and that seemed to work too. Overall took about 30-45 minutes to remove the majority and about more than an hour to get it all off completely. To make sure it’s completely off use a flashlight and point it at the screen.

⟐ Commented May 09, 2026 at 20:09 MST

The widgets are stored within /System/Library/CoreServicesBut Notes & Reminders are not there anymore (Maybe some others also have gone).

Unable to set weather location

Bluetooth Sharing has gone, but Bluetooth is on as I use a Magic Mouse II without any issues.

I also CANNOT change 'Open with default app' for example .mp3 or .mp4 opens with either Books, Music, Audacity, QT Player (All are different), even when I change to VLC as it always was with before via various methods NONE are changed so they all open with my preferred app. No matter what I try nothing seems to change anything, GET INFO (Set Default), Right Click (Open with other...) or even with App Cleaner app to set default app by extension etc....

This is really bugging me as I do not want to perform a complete clean install as I have a dual boot system and many files. We can rule out using Time Machine as that maybe will not solve it as from experience TM might still bring over the corrupted settings.... Is there a preferences file that I can delete or restore if so which one? Otherwise, system is running fine, these are my only issues noticed so far since a week or so. I have no dodgy software installed, nothing recently installed, no updates have been done (None to do anyway as all is up to date)..... I have booted into safe mode, rebooted as normal, but it has made no difference. Mystified on this as it is something I am usually good at fixing.

I found this link about widgets but no joy .

⟐ Answered May 04, 2026 at 8:41 MST

This is the second time I’ve replaced my battery with an ifixit battery and this is the second time this issue has came up. After replacing the battery and running the calibration cycle, I would use my laptop on its battery and somewhere around 70%-60% battery level, the battery level would just shoot down to 7%.

Initially on the first time around with replacing the battery, I just figured they sent me a faulty battery, but didn’t have time to buy another one and change it out, so i lived with the power adapter. I finally had a chance to replace it to a new battery, but the same thing just happened. Now, Im hoping to find some answers from you all if I have another faulty battery or some other insight on what it might can be.

Appreciate whatever insight provided!

UPDATE

Here’s a photo with the coconut battery app. In the screenshot under the “BATTERY (last 12 hours)” you can see the instant drop in battery level.

UPDATE #2

at 50% charge

at 100% charge

UPDATE #3

Screenshot charging from 0% to 50%

⟐ Answered April 27, 2026 at 7:38 MST

It is possible to enter Internet recovery mode, startup disk selection mode, Apple Diagnostics by using Startup key combinations.

But when I try to load recovery disk or MacOS boot disk(which show apple logo), it just boot loop.

I tried resetting SMC/NVRAM and it did nothing.

What's happening on my Macbook? I have no idea.

⟐ Answered April 16, 2026 at 10:41 MST

I'm not sure what just happened.

I cleaned my screen with a tiny bit of water, but I guess there might have been a bit too much. I guess I was pressing down on the cloth to get rid of something in the corner. I've done this many times before without issue, but now there is a huge light blotch in the left corner of my screen. There is an odd rectangular shape near the bottom too that doesn't make much sense. Take a look at this image of a completely white window:

https://i.imgur.com/fp4G5IY.jpg

I've read that the classic rice method, and or heating the computer up for a long period of time might help it dry, but I'm not entirely sure it's only water that's the problem.

Anyways, hoping someone can help me understand the damage I've done and what I might be able to do, other than paying for a replacement :D. Thanks.

Time seems to have healed all wounds.

I ran the computer hot with a 'while true' loop for a couple hours and it burned most of the water off, and what was left is slowly disappearing.

⟐ Commented April 14, 2026 at 8:46 MST

I researched a lot online and did the following:

• Disabled Energy Saver - Automatic Graphics Switching on both Battery and Power Adapter mode
• Disabled Spotlight indexing for specific types of content and also added folders like “/System” in the Privacy settings
• Reset the System Management Controller (SMC)
• Performed the Apple Diagnostics test (ADT - some older websites called it the Apple Hardware Test - AHT) and had no issues come from that.
• I also use Google Drive’s “Backup and Sync” and do lots of web development with `node_modules` folders, that can have 10s of thousands of small files which I think results in CPU churn. I’ve disabled it now.
• Shut down the computer and turned it back on. Still get same issues with the external monitor.

Now with no external monitor plugged in, every once and a while the kernel_task rises up to 300% and sometimes rarely to 500%. I’m curious if it is a software thing or a hardware thing. To me it seems more like a software thing.

I use VS Code for programming which can have a lot of background tasks, same with using node/npm which can probably be doing lots in the background. I also run iStat v6.30, and sadly I have only 21 GB of free space on my HDD (out of 500 GB…). Often I also have Slack open, and I know that’s a web app using Electron to run as a desktop application, which can be notorious for performance.

Often the fans can run high as well. I often suspect it is either due to the VS Code/npm/node/Slack thing, or kernel_task, or maybe something else I’m unaware about.

When checking memory usage via iStat, I can see that kernel_task is using 1.61 GB (oof, Firefox is using 6.36 GB).

Things I haven’t tried yet:

• Cleaning out more free space from HDD
• Using plain HDMI cable into the HDMI cable port
• Taking MBP apart and cleaning any potential dust

Has anyone had similar experience with this issue and how to address it?

OS: 10.13.6

Processor: 2.5 GHz Intel Core i7

Memory: 16 GB 1600 MHz DDR3

Graphics: AMD Radeon R9 M370X 2048 MB, Intel Iris Pro 1536 MB

⟐ Commented April 10, 2026 at 3:05 MST

I never tried this method yet just wondering if there is another method possible, the system is running nice and smooth apart from this 'issue'. It seems that I will need to do a clean install again to resolve this. @danj Any Idea on how to 'resolve this'?

UPDATE 06/04/26 I booted externally into Catalina & then Monterey (Internally & Externally). I Clean installed Catalina externally & booted. I used OCLP to install Sequoia but STILL we have the firmware update which does not install. I guess we have to wipe the SSD (Original 512 GB SSD from the unit) which is still installed, and clean install either El Capitan or Monterey to see if that clears the issue.

⟐ Edited by author April 06, 2026 at 18:40 MST

I have spilled bit of tea (no sugar) on my MacBook Pro 2015 (top right keyboard area, so around the right fan).

I have switched it off immediately and dried it for 3 days

I have switched it on today, it is working but kinda very slow.

I have IStat Menus:

All stats are looking fine except:

*Intel Iris GPU temperature at 0 degrees.

*High Kernel in my processes (around 500) and high CPU usage.

*High amperage CPU High (CPU, I/O) (95,8 A) and Radeon GPU core (75)

-> When the GPU switch to AMD, temperature is normal (36 degrees).

I have followed the steps from IfixIt to open it and remove the right fan: unplug battery, remove WiFi card, remove the right fan.

Brushed everything around that area with alcohol 96, but the issue is still here.

I do not know what to do as next step…

I feel I could continue the cleaning, bit deeper but I am not sure :-(

Do you have suggestions?

Thanks a lot for your help

EDIT 29.03.2026

Tanks a lot for the help!

I have taken off the logic board and indeed it was bit damaged below. I have cleaned all the impacted areas with iso alcool 96. If you see other areas that I should clean up let me know :)

Before:

After:

⟐ Commented March 29, 2026 at 14:21 MST

the burnt section lifted up where can I find that block and what is it? The one labeled CN

that little CN chip is the only thing ai saw lifted and well with carbon build up. Not sure where to find that number on the board but I have a picture with the serial# and information if that helps some.

⟐ Answered March 21, 2026 at 10:01 MST

My Mid 2015 A1398 15" Macbook Pro needed new speakers.

I bought replacement speakers & after all the hassle of installing them, they sound truly awful & with very low output. The connections are firm.

I then sought & bought genuine Apple Speakers which have the printed markings on them.

The Speakers in my MBP have 6 Connecters at the end of the cables but these replacement genuine Apple speakers who the seller confirmed also came from a 15" A1398 2015 MBP have only 4 Connectors - two at each end with the middle ones missing.

I really do not want to go through the hassle & time it takes to replace the Speakers only to then find these 4 connector also will have issues.

Can anyone tell me definitively if these 4 Connector ones will sound just as good & as loud as the 6 Connector ones? I was thinking maybe they were for 2012-2014 models & Apple might have upgraded with 6 Connectors on the 2015 model?

Many Thanks!

⟐ Answer accepted March 07, 2026 at 7:01 MST

Our collection of Magsafe 2 chargers didn't have an +80W charger. I got my Magsafe 1 to 2 adapter and tried an 85W brick. It would get a quarter of the way through booting and then would boot loop back to the start. Seems that everything I was seeing of 15" pros can't run without the battery appears to be true.

My question, is there a way to take the existing battery board and attach something to it to give the laptop the oomph it needs in times like booting up, and can withstand being plugged in a lot? I'm not an expert on the circuitry and software involved in Macs charge by any means, but I figured that there would be people on here that'd know. Or know someone that knows.

My drive for this is that it feels like getting a good quality battery over and over again doesn't feel feasible in the long term for these machines. And it is definitely not cost effective for the places that people dump otherwise working devices on. I'd like to find an alternative if possible.

⟐ Answer edited February 16, 2026 at 19:50 MST

I have mid 2015 15" Macbook Pro with i7 4870hq CPU.

I installed Volta app to undervolt and for measurement istats and intel power gadget.

With trial and error i found that i can go for up to -85mV. Can go for -95mV but it doesn't differ in terms of performance.

Tested the performance with cinebench r20, i get around %8-10 performance increase but i mostly get around 95-98 degrees temperature on CPU. It gets hot so quickly. I couldn't make it cooler much with undervolting. I think CPU idle degree is a little bit lower, like 55 to 47 degrees.

I installed mac fans control and increased the fans to their max rpms but didn't change anything.

Is there anything i can do more? What would be your recommendations?

I used cinebench as benchmark tool, what can i use in addition? I used geekbench but i get a little bit lower results like 5-20 points.

Thanks

⟐ Commented February 13, 2026 at 17:37 MST

The laptop base is destroyed but the display is in great condition. Is it possible to connect the Retina display to a desktop computer (my iMac) via HDMI or Thunderbolt or some other type of connection?

I assume I'd have to do some creative wiring and supply power to the screen to get this working. Have you ever seen this or come across anything like this?

⟐ Answered February 10, 2026 at 18:05 MST

I have a MacBook Pro mid-2015 15” Retina Display, A1398, EMC 2910, board number 820-00426-A, 16gb RAM, i7 core, 2.8ghz, Discrete Graphics.

I got this MacBook over a year ago, and about six months ago, the charger, and charging port area started getting really hot. (In my lack of knowledge, I was using a cheap knockoff MagSafe.)

It still worked fine, so I continued to use it. Then it started to only work intermittently, and I’d have to fiddle with the connection to get it to charge. Finally the charger seemed to die, and would not charge my laptop, showing no indicator light until occasionally AFTER being unplugged from the MacBook.

Wanting a reliable charger, I spent the $80+ to get a new MagSafe directly from Apple. When it arrived, I plugged it in, with no response; no light, not fans spinning, nothing.

Having had no previous experience repairing devices, I looked up all the YouTube videos I could, and tried the SMC and NVRAM resets many times.

Thinking it was the DC-in board, I bought and installed a replacement, but still got no light. I then replaced the battery, and my MacBook turned on, the battery having arrived with 82% charge, but still there was no charging. I replaced the right IO board, as well, and even tried to replace the motherboard (though the eBay motherboard I got was a scam, and was in fact worse than the existing board.

Since then, I have put it on the shelf. I recently got back into it, as our old MacBooks are becoming insufficient, or breaking. I got myself a multimeter, and the boardview and schematics for my board number, and have run several diode/continuity tests on several of the main power rails, and other than under the heat sink, which I can’t remove yet because I have no replacement thermal paste yet. Everything seems in order (other than what seems like there might be some corrosion under the heat sink), though I can’t figure out how to get the multimeter to measure the DC voltage the board is receiving.

Is there any component under the heat sink that could prevent charging if corroded? The MacBook runs perfectly with battery power, other than not charging, though the battery has long since died.

I know that neither the battery or the charger is not the problem, because I have tested both the old and new batteries, and the charger with someone else’s A1398 MacBook, and they work fine.

Sorry this is long, I just wanted to be detailed so the problem will be as obvious as possible to those who might know how to recognize it.

I have no soldering tools, or heat rework station, though I’m willing to get them if need be, I would just really like to avoid component level repair.

Can anyone help me? I really need this to be fixed, and can’t afford to get a replacement.

Front side of motherboard:

Back side of motherboard:

R7120 and R7122 components:

Charge port area:

R7120:

PP3V42_G3H Test Pad:

U7100 Pin 14:

Other motherboard missing component:

⟐ Commented January 27, 2026 at 11:35 MST

The strange thing is that after the low battery screen, I can wake my computer with the power adapter and it will always pick up from some high percentage like 10-40 or in my case, 100%. But once I wake the computer with the charger, I am able to use it like normal and drain it down to maybe 20% on the first drain cycle then down to 2% on the second drain cycle.

My main question here is how do I actually calibrate my battery to prevent it from shutting off at random percentages as I already performed the 100->0 drain attempt like 3 or 4 times and performed all the SMC resets and PRAM resets but it still shuts off randomly for no reason. Sometimes it will die at 100% and sometimes I can get it down to 1% before dying.

Is it because of the battery or something else? My battery is around 71% health but only around 500 charge cycles so it's not that bad but I don't know if the age is causing it to not handle high load spikes then just dying and requiring a charger for power up. Shouldn't my computer be smart enough to throttle itself to not cause random shutdowns?

⟐ Answer accepted January 20, 2026 at 23:59 MST

WiFi works fine on multiple other devices. Someone had a similar problem and a new I/O cable was suggested? Maybe a new card?

I'm replacing the battery anyway, so if there is a fix for this, it would be great to do it at the same time. Thanks.

⟐ Commented January 11, 2026 at 8:42 MST