HAC-CPU-01 Strange sleep issue, battery drain

Nintendo Questions Nintendo Switch
1

Hi,
I have a launch Nintendo Switch that has a strange problem.
At first, I noticed an intense battery drain while in sleep mode. The battery would die completely within hours. However, it would not drain if the switch is turned off.
Then, I noticed several problems while in sleep mode, in comparison to other Switches:

  • When plugged to a computer, Windows will make the “connect” sound every second when the switch is in sleep mode. Usually, Windows will make no sound in that situation.
  • When a game is run and the Switch is put in sleep mode, the connected joycons will vibrate faintly every second.

For me, it clearly shows that the CPU is waken up every second, causing the battery drain.
So I need help… Does somebody know which components are responsible to the switch sleep mode?
Or is it a software issue? I always ran an official firmware on it, except several times where I ran Hekate to launch Ubuntu.
A repair shop examined the motherboard and didn’t find any apparent short. He said he looked with a thermal camera.
Thanks for your help!

2

I made some measurements. In sleep mode, the values are really not stable. There is a spike every second or so, where the voltage goes high. Is the voltage regulator chip max77621 faulty, or one of its nearby components?

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3

I have one that keeps waking up after turning to sleep. I believe its the same ic problem as urs. Still trying to figure out which ic it is though. Messaging here to see updates. But will update my findings if i come across anything

4

This should be a Problem with the mosfets.
Check the mosfets above the usb type c Port, I would replace all 3 with some from donor Boards