Samsung Galaxy note 9 shutting down/restarting on its own

[Daniel4321]

To get right into the known problems I've had my note 9 since 2018 and sometime early last year(2022) I've noticed my battery would die within 5-10 mins once it crossed 20% charge.

The battery would otherwise work properly and hold its charge like normal as long as its above 20%, also there's no problem with charging the device I just treated 20% as the new 0% with that said I know the battery needs replacing.

 

Everything else functions as intended with the exception of the fingerprint scanner missing a few beats on occasion but nothing serious, fast-forward to sometime last week I had to use my flash on my phone for an extended period of time (if I had to guess maybe like 10 mins continuous usage with a break and another 10 mins and repeat about 3 times). On the same night while I was using the flash I noticed that my fingerprint scanner bugged out hard(I assume it was the fingerprint scanner because it gave the same exact vibration for when the fingerprint has a miss-read) and my phone started pulsing back-to-back-to-back vibrating like crazy so I unlocked my phone using the pin and the vibration stopped. I've only had a similar problem like that when the scanner was wet but not as extreme.

 

From that night my phone started rebooting on its own consistently every 8-10 mins (I did time it), so I checked online to see if anyone else had the same problem and I came across a reddit post with the same problem, the solution to his problem was solved by removing the fingerprint as a form of security. So I did the same and it DID help my situation but it didn't solve it, my phone still reboots on its own (but that happens alot less often now) my phone mostly shuts off by itself randomly and I have to turn it back on myself, I haven't been able to find a pattern or a reason for it to do so.

 

At this point I'm not sure what's the cause for this problem since disabling the fingerprint scanner did help and I haven't used the flash up until last night and the phone turned itself off almost immediately.

I guess my question is do I replace the battery and fingerprint scanner or its some other problem that can cause this?

Is it time to get a new phone lmao (I really don't want to I love this thing).

[Brando212]

you could try replacing the battery but there is the chance it doesn't help. it's up to you if it's worth spending money on a 'maybe' fix.

 

Personally I would start to look at upgrading. Since you like the Note you'd probably like the S Ultra offerings since they're basically the successor to the Notes and even include the pen.

[Daniel4321]

@Brando212That's the thing I really don't want to spend any extra on a 'maybe' fix since the S Ultra line up is still quite expensive even on the used market, so I'm just open to any reasons as to what's the cause or any solutions before I start spending any money.

[Applefreak]

25 minutes ago, Daniel4321 said:

To get right into the known problems I've had my note 9 since 2018 and sometime early last year(2022) I've noticed my battery would die within 5-10 mins once it crossed 20% charge.

The battery would otherwise work properly and hold its charge like normal as long as its above 20%, also there's no problem with charging the device I just treated 20% as the new 0% with that said I know the battery needs replacing.

 

Everything else functions as intended with the exception of the fingerprint scanner missing a few beats on occasion but nothing serious, fast-forward to sometime last week I had to use my flash on my phone for an extended period of time (if I had to guess maybe like 10 mins continuous usage with a break and another 10 mins and repeat about 3 times). On the same night while I was using the flash I noticed that my fingerprint scanner bugged out hard(I assume it was the fingerprint scanner because it gave the same exact vibration for when the fingerprint has a miss-read) and my phone started pulsing back-to-back-to-back vibrating like crazy so I unlocked my phone using the pin and the vibration stopped. I've only had a similar problem like that when the scanner was wet but not as extreme.

 

From that night my phone started rebooting on its own consistently every 8-10 mins (I did time it), so I checked online to see if anyone else had the same problem and I came across a reddit post with the same problem, the solution to his problem was solved by removing the fingerprint as a form of security. So I did the same and it DID help my situation but it didn't solve it, my phone still reboots on its own (but that happens alot less often now) my phone mostly shuts off by itself randomly and I have to turn it back on myself, I haven't been able to find a pattern or a reason for it to do so.

 

At this point I'm not sure what's the cause for this problem since disabling the fingerprint scanner did help and I haven't used the flash up until last night and the phone turned itself off almost immediately.

I guess my question is do I replace the battery and fingerprint scanner or its some other problem that can cause this?

Is it time to get a new phone lmao (I really don't want to I love this thing).

Without having the phone open I could not say for certain but you have already told us the battery is bad. Everything inside a phone grounds to the battery. If the connection is bad or unstable (meaning voltage), all kinds of things can go wrong. Replacing the battery can be done in an hour by a professional, I don't like doing it myself but it works with the ifixit kit for phone repairs, just takes some time and patience to loosen up the glue. Unless the phone has been dropped or experienced high humidity or an excess of water, I tend to believe it is the battery. If it was it could be the motherboard as well but Samsung does not provide diagnostic tools and plans to debug it so replacing the battery seems to be the only thing you can feasibly do or get done. Hope you can fix it, truly one of the best phones of all time in my book.

[Brando212]

10 minutes ago, Daniel4321 said:

@Brando212That's the thing I really don't want to spend any extra on a 'maybe' fix since the S Ultra line up is still quite expensive even on the used market, so I'm just open to any reasons as to what's the cause or any solutions before I start spending any money.

definitely understand that. the S Ultras hold their value almost as much as iPhones.

 

just to rule out anything stupid, have you tried a factory reset on your Note?

[Daniel4321]

@ApplefreakYah the biggest culprit so far is the battery, when I'm looking around some more if I see any other similar issues and it points to the battery I'll lean more on replacing the battery rather than getting a new phone.

 

@Brando212Actually no I haven't factory reset my phone yet mostly because the few threads I've been on with similar issues all say to do that and the problem is still there and it also had no updates around that time and I didn't install any new apps or anything like that, maybe when I'm closer to making a decision on replacing the battery or getting a new phone I'll do that.

[Brando212]

10 minutes ago, Daniel4321 said:

@Brando212Actually no I haven't factory reset my phone yet mostly because the few threads I've been on with similar issues all say to do that and the problem is still there and it also had no updates around that time and I didn't install any new apps or anything like that, maybe when I'm closer to making a decision on replacing the battery or getting a new phone I'll do that.

Yeah may not help but is always a good and easy test to rule out corruption/bit-rot bloat and that. We all know how bad Android is about becoming cluttered and slow over time lol

[Daniel4321]

Just updating and closing off this thread, I ended up replacing the battery, fingerprint scanner and the charging port. I didn't know that in the Samsung's diagnostics you can test the fingerprint scanner so I did and turns out there where 3 fails out of 7 tests, I'm almost sure the fingerprint was the root cause since the phone would otherwise function completely fine once the battery was over 20% (before the shutting off issue) ruling out the battery. The charging port was changed just because I was already in the phone and I plug my phone in daily.

 

It's been about a week since I replaced the parts and all of the issues are gone glad I only had to spend $50 rather than buying a new phone lol