"Unable to charge" Message, USB Data & M92 Output Issues

I have two Switches which boot & slow charge fine. but When the OS is bootet up, it shows a message saying “Charging not possible”.

I already replaced the M92 on both mainboards without success. One thing I noticed it that on both boards the USB Bus seems to be busted. Measuring the resistance of USB D-/D+ to GND I get about 1.5MOhm on a working switch. The broken ones have either about 50kOhm on one Data pin & the other has multiple MOhms [50MOhm-ish] to GND.

Did anybody else ever came around this issues?

Also one of them has 40 Ohms to GND on the Output Pin 6 of the M92 but works fine. Already unsoldered a few components around the board, but idk what causes this low impedance.

The usb data lines D-/D+ (testpad 2 & 3) are going to a esd protection ic (7C) and then to filter. There are board version where the esd protection ic is not soldered on. If the problem is not at one of this both components, the problem might be at the end of the lines, direct under the soc.

On the backside of the battery connector is a fuel gauge. Maybe the “Charging not pssible” problem is starting here. Values are in diode mode. No battery, no charger, red probe on ground.

Good readings their should be approx 5/5.6Meg (depending on lead polarity) resistance accross both D-/D+ should be approx 14meg.

Assuming readings direct on the board are good but not via USB then points to a bad USB.

Of course assuming erista and not mariko

USB Data: Yea, i guess it’s busted in the APU. Consoles are also not recognized as USB devices on my PC… so no RCM :frowning:

Fuel gauge: My measurings are pretty close:
383 = 362
601 = 588
530 = 466
530 = 466

I wouldn’t rule out USB fault here, poor soldering or grime could cause the same symptoms, verify USB via breakout using Calvins diode map (usb needs to be present to duplicate) and after verify readings on esd diode.

If still no luck then i’ll tell you where to measure to verify soc

I checked like all diagrams i could find from @Calvin - if there is a complete one plz let me know.

All reading seem pretty normal so far. Except the 0.040 on 3v3 & OL on USB Data.

I have just faced into similar issue. The switch is charging slow with a 3rd party dock and usb tester but as soon as it would switch to fast charging there is the unable to charge message. As soon as I use the original charger it charges perfectly again. I do not have an usb C tester but I can measure the 15V on the fuse and it is charging pretty fast. Cannot be that the newer Switch is recognizing somehow that the charger is not genuin and this is causing this messsage with a 3rd party charger?

The Switch talks to the charger to enable fast charging. The usb c from Nintendo is not entirely standard, so there are high chances, that a 3rd party charger and the Switch are not working propperly together. And the M92t36 ic is sensitive for false voltages.

What is a little bit strange for me here is that in the past I have already repaired ca 5‐6 Switch and all of them was fast charging (with 5V and 1.4A only but it was fast charging and not only with 0,47A) with the exact same phone charger and power bank I have tried to use now. This one is now only fast charging with the original charger and with my Lenovo laptop charger which are capable for the 15V fast charging.
What is a difference with this switch is that it is already the slightly newer non-patchable version and all the previous ones were the ood version. Maybe they modified something…

It is a different protocol, Nintendo does it a little differently.

It could also feasibly be down to FW version.