Switch wont charge or turn on. Strange issue happened

Hi all.

Bare with me, I’m no expert (little hobby) and this is the first in-depth switch I’m trying to repair.

Got a switch here HAC-001 with the mainboard reading HAC-CPU-01.

Getting no image on the screen, won’t turn on. No charge icon but it does seem to charge (or did, i’ll get to that)

Originally I couldn’t find any shorts, but I saw a video online of a guy testing the voltage at what looks like a test pad just above the charge port near the water damage mark. I checked mine and it was reading 17.26v which if I’m not mistaken is way too high and should be near 15v (correct me if I’m wrong).

I saw some posts on this forum which says to check Pin 5 and 6 of the M92T36 chip, mine was reading 3.82v for both, however, Pin 9 was reading 17.17V (not sure if that’s normal but I assume not).

I have attached an image of my measurements

link to img imgur. com/oqDXXv3 (space between r and .com)

The battery was charging but it was slow charging and I could see the numbers increase when testing across my multiple meter. I left it on all night and the battery reached 4.60v (not sure what it should be at full charge).

Now I have an additional problem, im not sure if I caused while testing the voltage of components or if the high voltage charging finally did something but i now have a short on the cap above the M92T36 chip.

link to img imgur. com/cGUQhdf (space between r and .com)

Pin 5 and 6 read the same 3.82v while Pin 9 is now 0v and the test pad above the charge port is also on 0v so this says its not longer charging.

Firstly if the M92T36 is faulty would it still allow a slow charge? and can any one confirm if this chip being faulty would cause no image/no charge icon.

Is there anything you can point to that would be the reason for the high 17.17v charge.

Many thanks for any help you can give me.

(Also no expert, but I have experience with Nintendo switches)

I have never been able to charge a switch if the M92T36 chip is faulty. I use a multi-meter to do a “continuity test” I believe that’s what the mode is called. Tronicsfix did it on their YT many many times. But I would do that if you have a multi-meter in hand.

I usually test all those little diodes/capacitors (I don’t know the actual term).
just to see if the PI3USB or the M93T36 chips are bad or not.

I’m not very good at explaining but the test will show you if there’s a short from those chips or not (at least in my experience).

So the M92T’s main job is to marshall USB Type-C connections and to make sense of connector orientation etc (it drives the PI3USB chip on the other side using 3 discrete lines). The PI3USB deals with display over USB Type-C and USB-3 services etc. and will not be your problem. The Switch will run fine on its own internal LCD with PI3USB IC removed!

So I think you are right to focus on the M92T as this is likely to be the problem. When you were getting 17v on Pin 9, was that with the Nintendo official charger?

You may have an LCD backlight issue which can often fool people. If you put the screen under a bright light, you can sometimes see the faint image of the Switch boot logo. Worth checking the LCD connector as that’s easy to damage too.

The short on that cap is a concern. This is the VCONN in feed that supplies OTG peripherals, but is symptomatic of IC damage. Steve’s fault diagnosis videos will help you trace the likely culprit. Don’t assume it’s the M92 just because it’s close by!

I was able to solve this issue by replacing the M93T36 chip.

However, its been a long process and still not any closer to booting the switch.

I’m able to get into Hekate but that’s it. Stock FW won’t boot, neither will CFW.

So I’m currently reaching these issues.

I appreciate the comments.