A friend gave me a switch lite with no power (HDH-CPU-02).
I opened to take some measurements and found that pin 38 or 39 can’t remember which one was shorted to ground.
checked for shorts on the other chips and none was shorted.
so i replaced the m92t36 and the short was gone. connected LCD, touch, fan, L FPC and a test battery and powered on and it was working fine, connected charging cable and charging was fine.
then powered off and reconnected original and plugged on charge and it was drawing 0.48A then 0.47A and 0.46A and it stayed on 0.46A and did not power on again.
checked the m92t36 again and pin 6 was shorted. I replaced it again, thought maybe it was a bad chip, second chip same thing it’ll power on the after shutdown m92t36 gets shorted.
2 weeks ago i had replaced the m92t36 chip and just left the board to the side, and on Wednesday powered on by mistake and it was working fine for 2 days. powers on, off and charging no problem till today when i powered off to put everything back together and m92t36 is dead again with pin 6 (0v) and 18 (0.68v). connecting to charger 15v 0.00A drawn.
no pins on the USB port are shorting also with m92t36 removed checked the pads and none are bridged.
I thought maybe bad batch of chips, but i used 5 on other switches with problems.
when i checked the error history in settings it was filled with Error 2101-0001.
hope someone has some ideas what might be causing this.
In almost every case where I have had issues with Pin 5 or 6 after replacing M92T36 it has been an issue with P13USB. Check if the large capacitor by P13USB is shorted, if it is, pull P13USB and see if the short is gone. If it is, replace P13USB. If the short is still present then it is an issue elsewhere.
The switch lite does not have p13usb. If i would to guess why the short. I would replace the bq chip as well. The charging circuit is usually the bq, m92, usb port and fuel gauge I think
The switch lite does not have p13usb. If i would to guess why the short. I would replace the bq chip as well. The charging circuit is usually the bq, m92, usb port and fuel gauge I think
My bad - I must have missed the part about Switch Lite!
I mean you could always play the cat and mouse game and replace and put back the mosfet and check if the short is gone. Or you could try voltage injection.
This board is trolling me now. I was about to replace those 4 components, but decided to just connect the board to charger and it started charging and it’s powering on now.
Gonna test for the next 2 day’s before replacing bq and fuel gauge. I want to write down the resistance and diode mode readings when it’s showing as shorted.
