Hardware Switch Lite Coil Whine (Not related to the plug)

[rdlf4]

My Switch Lite whines when it's booting, but that only happens during the Nintendo logo screen.
Right after that, screen goes to black and then when the Switch logo appears, the whine is gone.
After entering sleep state, if I attempt to wake up the handheld soon after that, (5 to 8 minutes after sleep mode has started), it wakes up just fine.
If I leave it sleeping for longer than 10 minutes, I can hear coil whine upon waking it up and this buzz goes on and on. Curiously, after coil whine has started, if I press the power button, making the Switch Lite go to sleep, and then wake it up right after that, the whine is gone. Oh and this is important: Every time the Switch Lite coil whines, screen brightness goes all the way up to 100% and the brightness slider won't set it down, it won't work. Without coil whine, brightness slider works just fine.
I attempted to listen to it very carefully, and it seems it leads to this area:

From another angle:

Now, it could have to do with something from the other side of the board but I think it sounds way louder from the side I took the picture.

What could be my issue?
Please help me out. Thanks in advance.

 

[rdlf4]

Here's a video to better illustrate what's going on:


I need some help with this, what could be the cause to make that happen sometimes upon wake up?
Would that have to do with any sort of short? Is that an indication that something's about to blow up?

 

[rdlf4]

Upon further testing, I've come to the conclusion that whenever "coil whine" happens, it is not to tell me that a component is working - rather, it's from the potentiometer saying something is wrong.
That's why screen brightness goes all the way up to 100% and will be stuck at that during coil whine. Trying to lower it down doesn't work, so the potentiometer doesn't work.
However, pressing the power button to enter sleep mode and then pressing it again right away and everything works, screen brightness goes back to where it was.
So why is the potentiometer behaving like that? Could it be because another component is providing more current than it can handle? Could it be those caps on the daughterboard, next to the backlight? I need some answers :S

 

[popy]

Coil whine comes typically from an DC-DC converter or sort of power converter.
Usally these types of step-down or step-up converter are switching on/off the DC input voltage very fast. The frequency depends on the converter chip (base frequency) and can varying depending on load (there are also fixed types, which just changing the pwm duty cycle). These frequency produces side frequencys, which some, we can hear (coming from the coil, in your case white component).

Long answer short meaning : coil whine must not mean there is something wrong or defect with the DC-DC converter.

I think in your case, the control of the backlight DC-DC converter (which you stated doesn't work correctly) is the culprit or the DC-DC has some damage.

Do you have warranty?
I would suggest you to replace the switch.

If you don't have warranty, a trick is to glue the coil down on the pcb. Just use super glue an let it flow under the coil. Maybe it helps.

pOpY

Gesendet von meinem ONEPLUS A6013 mit Tapatalk

 

[rdlf4]

Coil whine comes typically from an DC-DC converter or sort of power converter.
Usally these types of step-down or step-up converter are switching on/off the DC input voltage very fast. The frequency depends on the converter chip (base frequency) and can varying depending on load (there are also fixed types, which just changing the pwm duty cycle). These frequency produces side frequencys, which some, we can hear (coming from the coil, in your case white component).

Long answer short meaning : coil whine must not mean there is something wrong or defect with the DC-DC converter.

I think in your case, the control of the backlight DC-DC converter (which you stated doesn't work correctly) is the culprit or the DC-DC has some damage.

Do you have warranty?
I would suggest you to replace the switch.

If you don't have warranty, a trick is to glue the coil down on the pcb. Just use super glue an let it flow under the coil. Maybe it helps.

pOpY

Gesendet von meinem ONEPLUS A6013 mit Tapatalk

Thank you for replying.
I'm trying to track it down to its root and found that the interconnect cable might be the culprit.
So I tried to remove the original one and solder down a replacement.
As you can see from this picture, there are two components right next to the pads of said connector:

Upon removing the solder that was left, I ended up knocking that resistor off and couldn't find it anywhere.
Would you happen to know the value of it? Please share it with me if you do.

 

[jkyoho]

https://gbatemp.net/threads/switch-lite-volume-up-not-working-not-ffc.583893/

check this may helpful

 

[rdlf4]

https://gbatemp.net/threads/switch-lite-volume-up-not-working-not-ffc.583893/

check this may helpful

Thank you for that.
It seems my Switch Lite might have bigger issues than I anticipated.
This diode is beeping from both pads (back of handheld):


Still on the back, those caps (highlighted in red) around MAX77620HEWJ power management IC are shorting to ground:


And on the front, under the APU, those caps around MAX77812 IC are shorting to ground:


If anyone could reproduce these results to help me pinpoint what's wrong with this Switch Lite, that'd be very helpful.
Thanks in advance.

 

[Djoe_]

With you find the problem because I meet the same symptoms after buying a Switch lite where liquid has flowed over it.