• Firefox/YouTube: Video plays without audio.
• Safari/YouTube: Sometimes no audio/video (but seeker moves, subtitles come). Sometimes video just stuck on loading—in which case after a while it tells me to “try restarting the device” if playback doesn’t resume.
• Apple TV: Media cannot load/play. Instantly media player is “killed” for the lack of a better term.
• Apple Music: Track auto skips to next. Similar to Apple TV. It attempts to play, can’t play, then instead of killing the media it skips to next song, repeat.
• Many streaming services in Firefox, Chrome, Safari: The playback technically begins, I can see the seeker/playhead move in time and subtitles come and go, but video is black and there’s no sound.

What’s common in all scenarios is there’s no sound. It happened abruptly one day. Default device is set to “MacBook Pro Speakers”.

More strangely, in the past week I've been having this problem, there have been two times when it became completely fine. That too, mid-playback. And randomly, it goes away too. For example, most recently when it started working again, I was watching a video on YouTube. I pause it for a bit to do something and when I come back and resume it, suddenly there's no sound again.

Further clarifications:

• I opened OBS Studio and added window capture of Firefox while playing a YouTube video. The sound bar was not moving at all.
• I have removed all Bluetooth devices and kept Bluetooth off while I have tested all this.
• It's not just media, no alert sounds are coming either, including the boot-up sound.
• Sound works fine when using a headphone (via aux for example).
• No crackling or weird noise to tell me that speakers are damaged in any way. When they started working again twice randomy during the last week, they worked 100% fine with complete clarity and volume.

Video here.

MacBook Pro 16-inch 2021 with Apple M1 Pro, 16 GB RAM, and Sequoia 15.5 operating system.

⟐ Commented Mayıs 02, 2026 at 9:54 GMT-7

And yet the laptop does not work as usual. First time it took ages until it could load the log-in screen. And it didn't got better afterwards either. The "SYMPTOMS" include:

• very long response time to basic commands such as close the tab or move the cursor;
• battery status is not shown - neither on the tab nor in settings; I suppose the computer does not "see" it;
• fans start to work at full speed as soon as I open the lid and continue like this - no matter the task - and albeit MBP is not even warm.

That's it. I've got to say that I didn't exchange the battery. The only way I came into contact with it is at a step where the battery power connector is disconnected (and then connected); and the same with the battery board data cable.

I've read here and there about those "symptoms" and it seems that (1) working slowly with (2) fans at full speed albeit no need to cool the computer down indicates that my MBP is running in a safe mode. Well, I would like to know whether you guys think this too.

Where could have I done sth. wrong in the assembly to cause this behavior? Or what else could be the reason?

After going through the manual (MacBook Pro (16 Zoll, 2019) Display tauschen - iFixit Reparaturanleitung) again I believe to have narrowed down the list of possible causes to just four connections that might not sit just right:

1. 1. Display board flex cable (German: Flachbandkabel; step no. 19)
2. 2. Antenna cables (Antennenkabel; steps no. 22-23)
   3. Battery board data cable (Akkuplatinen-Datenkabel; steps no. 11-14)
3. 4. Battery power connector (Akkustrom Stecker; steps no. 15-16)

But I don't want to disassemble the computer just yet, bcs. I am still not sure whether the cause is not sth. else, e.g. faulty display (item) or I broke sth. else during the process. So who knows what the cause of the behavior described might be? And how to fix it.

@danj thank for advice. However, yesterday after posting this question I chatted with FixBot here. It wasn't completely precise, but in general I understood that the issue most likely lies within the bad battery data cable connection. Without doing diagnostics first I risked and disassembled the cover again to check connections manually. Now it works.

It's interesting, I thought that the issue was that one or both sides of the battery data cable weren't fully in the socket. AI said (falsely) that gold pins a) should be put face down to the logic board and b) they need to be full way in to make full contact with the socket. Both of which are false, however. I checked a) with a YT-video where this model gets disassembled - gold pins should face upwards, as in the photo (guide is correct). And b) can be checked with another YT-video too, but also I tried it this way and that way to get it fully inside and it's impossible. I might have even bended one side of golden pins slightly. So DO NOT do it. It's just strange that they do not go fully inside and also aren't really fixed (only with those tiny ears).

However, after reseating this battery data cable with the battery power connector in reverse order (first connect the battery data cable to the logic board side, which is away from the middle of the computer, then battery power connector, then another side of the battery data cable to the battery side, which is to the middle of the computer), it works. ''''

//This discrepancy remains in the guide bcs. there they just say "redo in reverse order to assemble", which means that the battery power connector gets connected before the battery data cable and, according to the FixBot, can cause a short circuit, esp. if cable is not inserted straight. ‼️

So I did not change anything as I see it; also checked other parts I touched during screen replacement procedures: everything looked perfectly aligned and I did not touch them. But believe it or not, after putting each screw back, plugging in the computer and turning it on, I got this: a) no roaring fans; b) usual processing speed; c) battery status is back. So just as it should be. The conclusion is: it was either bad connection of the cable to the socket or a ZIF brake maybe was not flat entirely; or exactly the order of the steps, as AI suggested (however in YT-video they also do it as in the guide: first power, then data).

I hope my detailed answer will help anyone facing similar issues after reassembly.

⟐ Edited by author Nisan 30, 2026 at 7:07 GMT-7

I'm experiencing weird issues with my MBP 16" I9 2.3GHZ, 32GB, 1TB, 5500 4GB.

I bought it second hand in October 2024 and due to some strike by Canada Post it stayed for a whole month in a warehouse, dead battery on delivery, the Touch ID was kaput, tried many resets and installs and nothing (no DFU yet).

Some time later, I began having some Kernel Panics here and there, once a month, not so persistent. But lately it began to happen too much in the 10's one after another.

I used it for long gaming sessions with an external ssd ( bootcamp ) not a single crash.

The kernel panics happened a lot when :

Apps running : Chrome, PremierePro, After Effect, Spotify...
Connected to : NVME enclosure, external USB C hub ( 4K HDMI + 2 ext. HDD ), Bluetooth connected to my AV receiver.

Lately I switched to using Safari only and weirdly no more crashes:
NVME enclosure connected + Pr + Ae + Bluetooth active, w/o external USB C HUB

Here is a conversation with Gemini documenting the crashes : https://gemini.google.com/share/e49e55d1...

Gemini is pointing to a faulty power rail or even a faulty T2 Chip ( management + BridgeOs).

I've tried to having some experts to diagnose the issue and all of them gave me the same advice "change the motherboard or better buy a new one".

Louis Rossmann won't be happy with their diagnosis, but yeah I get the struggle of putting in some work and having it fail again.

Right now I sincerely think it's a software issue, I tend to run a lot of renders over Ae & Pr and not a single crash, CPU and temps all high for 1 or two hours, only when an app as Chrome or Spotify ( chromium based app ) runs that I have the unresponsive for sometime before rebooting from a panicked kernel.

The report always states a random unresponsive processes, but I fell like the smoking gun is held by Chrome or Spotify, my proof is simple, they do happen a lot when I push it to the extreme, open new tabs of very taxing website (IG, FB marketplace) the kind of website that has too many layers to it...

Is there anything that I'm missing here ? Faulty hardware acceleration ? I typically run my Mac on dedicated GPU only. Any other hardware ? Or purely some corrupted firmware ( T2 related ).

I'm willing to do a DFU restore in the coming days with another Mac to attempt a recovery of the TouchID and a clean install, even though one quick visit to an Apple Store and they told me it was best to replace it for 200$ ( after a 1 hours diagnosis ).

Tanks again !!

⟐ Answered Nisan 29, 2026 at 19:06 GMT-7

⟐ Answered Nisan 29, 2026 at 14:45 GMT-7

Battery Terminal & Data PORT. On my MacBook Pro 16” M1 Max, snapped off or broke off when putting in new battery and I believe that was the reason why the battery it was not being recognized by the board because of the logic board connector,

I’m in desperate need for someone who can help me fix or find the parts name or number

(Battery Terminal & Data PORT)

because I’ve tried, can’t find or get anything

⟐ Answer accepted Nisan 27, 2026 at 7:20 GMT-7

⟐ Commented Nisan 26, 2026 at 13:09 GMT-7

So I tried replace the battery on the MacBook Pro 2141 and the step where the battery flex cable needed to disconnected by accident I lifted the connector that snapped.

Can new connector be soldered back with ease or this one need more repair?

So, I brought to the repair shop they soldered, but claiming there is issue with motherboard - it not powering up (Please note still with old battery on laptop) but I never had any signs of motherboard going bad, it was working prior this. I asked for technical report, they refused - said we cannot provide that, our system not allowing to print report. Total bs! So first - I need that data on the laptop, so I need data extraction, or should I try something else before that. Thanks

⟐ Commented Nisan 26, 2026 at 6:05 GMT-7

I've torn the lid angle sensor while trying to clean the inside of my computer. I've attempted to work around this by putting the computer to sleep before closing the lid however the screen turns back on as soon as it is closed. Also strange that the screen will stay on indefinitely until the battery is dead, even though i've changed my power savings settings are to turn the display off after one minute of inactivity. Its odd because if the sensor is broken and the computer thinks that it's still open, it should turn off after inactivity. The only solution i've found is to shut the computer off before closing it which is not ideal. Finally, i've found replacement cables online however i've been reading that this will need to be calibrated by a professional? Can anyone confirm if this is true?

Thank You

Thank you all for the wealth of information. Just to provide an update to you all, i made sure to purchase a used angle sensor that was taken from a working computer and replaced it on my own. So far everything works as it should!

⟐ Answered Nisan 22, 2026 at 19:22 GMT-7

⟐ Answered Nisan 20, 2026 at 4:48 GMT-7

⟐ Commented Nisan 15, 2026 at 13:08 GMT-7

⟐ Commented Nisan 08, 2026 at 1:12 GMT-7

Please help me figure this out. Does the keyboard backlight have its separate cable? How is it connected to the motherboard? If anyone has photos of this board and an example of how the power and control for the backlight are organized, I'd appreciate getting those photos. Could I have simply forgotten to reconnect a cable during the MacBook's reassembly?

Thank you, everyone!

⟐ Commented Mart 19, 2026 at 8:38 GMT-7

some people say the keyboard does vent out heat and that if you put a keyboard cover/skin on that it will eventually wear out (damage) the internal components, others say to monitor hardware temperatures if you cover the keyboard, etc.

all of this seems to indicate then that the keyboard actually vents out heat!??

but where are the vents in the keyboard then? this seems like a completely false rumor! i feel like snopes and we got to get to the bottom of this!

please help me find the truth.

thank you,

Mongo

⟐ Answer accepted Mart 18, 2026 at 4:36 GMT-7

⟐ Commented Mart 15, 2026 at 16:44 GMT-7

I would appreciate it if you could advise whether this can be repaired and the best way to proceed. If possible, please also let me know the estimated cost and the process for getting it fixed.

I have included a picture

of cable and connector

Added more photoo

⟐ Commented Mart 12, 2026 at 7:21 GMT-7

after installation I noticed a small dark spot in the top left corner that “pulses” or flickers slightly.

The seller says it had no issues before shipping,

Did I something wrong ? Should I re‑install the screen, or is it a panel issue from the start? Does it get worse over time, and is there any fix?

⟐ Answer edited Mart 11, 2026 at 9:14 GMT-7

Here is an info on the macbook battery

⟐ Commented Mart 07, 2026 at 16:49 GMT-7

I replaced the battery in my 2019 MacBook Pro 16" with the iFixit battery in July 2024. It has performed like a champ since then! Great battery!!

However, once I upgraded to Tahoe, the battery will now drain to about 50%, then instantly drop below 5% and go into shutdown mode. I have done multiple battery gage resets and also the SMC, NVRAM/PRAM resets with no success. It seems like the iFixit battery loses compatibility with the Tahoe OS.

Has anyone else experienced this sudden shutdown behavior and has had any success in debugging it without rolling back to Sequoia?

**UPDATE: I have added the Coconut Battery info as requested in a subsequent post.

⟐ Commented Şubat 25, 2026 at 13:51 GMT-7

I'm still guessing there is some annoying intermittent hardware fault, though.

Thank you everyone for your input and suggestions!

-------------

Might someone here have some experience with this?

I have an A2141 in, except for this crashing issue, is in excellent condition throughout. Low battery cycles, little SSD wear, amazing physical condition. Basically looks like it's been sitting on a desk its whole life. So it would be a shame for it to end up as parts.

The problem: Randomly, every few days or maybe once a day, MacOS crashes. No Shift Lock, screen stays on even with the lid closed. Nothing is reported in logs. On the charger, on battery, various chargers (also original), just a browser running, or lots of apps running. Normal or Low Power mode. Nothing in the environment seems to have any impact. It just happens sometimes at random. Temperatures normal too.

The crash can happen at any time regardless of activity, or even just sitting idle, and also when sat perfectly untouched, not even moved on a table.

Yet, except for the crashing, everything works 100%.

The problem appears on Tahoe as well as earlier MacOS versions, so I left it on Tahoe. (which is officially supported on this last-of-the-Intel generation)

Already attempted: All the usual reset SMC/PRAM procedures. Complete DFU reset and reinstalled Tahoe. Hence any firmware should have been rewritten...

As a hardware problem, the problem appears difficult to handle, as the crash is not easily reproduced.

Any ideas? Thank you for your help!

(added image - and yes in this case, the last shutdown was normal.)

⟐ Edited by author Şubat 19, 2026 at 7:24 GMT-7

These Macbooks are now around 4-5 years so it's not a bad idea to replace the thermal paste.

They're not obsolute so there will still be users who can benefit from a guide.

Update:

So I was able to open the MacBook and disassemble the motherboard with the video.

Since I'm comfortable around electronics (this isn't my first time opening up a MacBook, laptop, or even a smartphone), I did choose to replace the thermal paste on the cpu and gpu.

And honestly, after four years of service... Kind of disappointed about the original paste. Dan said that paste will last longer now due to improvements, but the original paste was crumbly as hell. Furthermore I noticed small blank spots on the cpu and it's heatsink, so not very good spread. The gpu did have a good spread. They definitely were generous with the paste on the gpu, because its surroundings were covered with paste too.

Cleaning wasn't difficult, as I said the paste was in a very crumbly state.

After cleaning I gave the copper plates of the heatsink and the cpu and gpu some time to evaporate the alcohol.

I used Noctua NT-H2 and used the "X" to spread the paste on both cpu and gpu.

The only annoying experience was to place back the motherboard in the case. I needed multiple attempts because there was always some small connector/ribbon cable underneath the motherboard. Ugh! After playing like an octopus for a while, I was able to place the motherboard back and with all connectors/ribbon cables out on top of it.

It's do-able but only for people who have a steady hand and... most of all... lots and lots of patience. Take your time. Take some breaks if you get tired or frustrated because the moment that you attempt to work a bit faster or anything like that... something will go wrong. I 100% guarantee that.

I made only one mistake. The connector cable from the left fan is incredibely fragile due to its L-shape (that's what I think). In trying to get the L-shape cable from underneath the board to the top on the board, I got a small tear in the ribbon cable. This fan no longer works. We learn from our mistakes. Should've taped the connector on top of the fan, I wouldn't had an issue to "fish" for the cable since it can't get trapped underneath the board that way. Already ordered a replacement fan.

The temperatures are amazing though. In idle I went from 60-63° to 46-51°. The one remaining fan is also a lot quieter. I'm not going to claim this huge difference to the new paste though. There was so much built up dust in the MacBook... I was genuinely surprised that the MacBook didn't have much higher temps in idle. Both fans were completly covered up in thick dust, and the outlets on both fans same thing. How it managed to get some kind of airflow through those thick dust is a mystery to me.

Anyway, I am very happy with the result. Yes, I did damage one fan connector, but one can only learn with making mishaps.

⟐ Commented Şubat 14, 2026 at 4:21 GMT-7