Not charging but everything else works fine

Nintendo Questions Nintendo Switch
#1

Hi guys Im currently stuck in a repair.
When i put in a working battery the console turns on as normal. It boots, I get sound, the touch is working fully, it docks and joycons get connected and work.
When I plug it in to either a usb phone charger or the oem charger I get the little lightning that tells me that it is charging BUT overtime the battery percentage just keeps declining and it doesnt charge.

Measuring around the BQ Chip i see that VBUS is getting 5 Volts. When I unplug the Battery and measure the BAT terminal of the Chip I get 0V but im not sure what it would show on a working switch.

The switch previously had a short inside the PI3USB Chip and because of that i replaced it and the M92 but the charging issue persists.

Any help is greatly appreciated!

#2

Check esd diode of usbc cc lines and that both cc pins have continuity from the charge port to the mt chip

If you unplug the battery the charge chip goes into a failure mode iirc
There are some pins on the charge chip which can tell you if it has detected a failure and if it even charges; they are described in the datasheet of the chip

If you can start hekate you can also get some more info how it charges if you do not have a usbc c/v meter

#3

I will check the usb lines and the charge chip in a minute.
I should also add that when i use a usb meter it measures 5Volts and 0Amps

#4

Ok so here is what I have found:
I have looked at the cc lines and they appear to be continuous to the respective tabs underneath to the m92t chip.
Checking the bq charge chips status pin its showing a constant low signal. The datasheet describes this behaviour as “charging” i get a reading of 4.6V with the charger plugged in on the PMID Pin of the bq24 all of the other pins on it read 0V.
I also have not been able to locate the esd diode you were refering to. I think i know where it should be but my motherboard does not have any component at that place just the bare copper of the circuit board. I attatched a picture that shows the component im referring to.

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Thanks again for your time!

#5

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back side also has a esd.(yellow circle)

It happened to me one time, after internal short M92T replaced, I also have to remove/replace this esd to get battery charge.

#6

Yeah I have read online about issues like this but sadly my board does not contain either of those two chips. Im speculating about the max77620 pmic chip not getting vbus power from the usb port but i dont have the datasheet for that and I have no idea what Voltage to expect on the components around it.

#7

Since your board turns on you can leave the pmic out, it has nothing to do with charging

Basically your usbc cable has either a resistor or chip that talks to the mt chip in the console (vbus goes also to that chip), then power goes to the charging chip and from there on to all the other parts

You can try to replace the charging ic and look if it changes something, could be that something is broken internally in it

#8

Ok thats good to know i was also thinking about just replacing the BQ only issue is that im scared of burning the joycon connector on the board thats next to it.
Is there any way to verify that it is the charging chip that is broken? Because when the console turns on from the charged battery and i then plug in the usb cable it shows me that the console thinks it is charging.
I will reassemble the console now and measure some of the data lines with my osciloscope and check the Voltage on all the pins around mt and bq chip. I will report back if I find anything interresting…
Thanks again for your help!

#9

Ok measuring didnt really show any signs of obvious damage. What i did notice is that windows doesn’t recognise a device plugged in when i connect the switch to my pc while the switch is running from battery power. When the console is running and i plug the cable in it displays the icon indicating its charging but again 0amps on the usb meter and battery percentage decreasing.

#10

Any updates, I have a switch with the same problem

Thanks

#11

Nothing new so far. Im still contemplating replaceing the BQ24193 Chip since i dont really think that it is the issue as this chip is not recieving any voltage on its data lines when the mainboard is plugged in.

#12

I have the new chip on order n will replace once it arrive. Will update here if it fixes my issue