I had a similar issue. It all started when I simultaneously used 12v adapter and Cheap Usb C Fast charger. Well the fast charger was actually connected to hdmi/gigabit ethernet dock and the dock connected to type C input of the tablet. The tablet did not like this and immediately started hard hanging after few seconds into desktop. This continued for few days and then eventually would not boot(no post, no screen). Just red led lit up for few secs and then nothing.
Disappointed, I kept aside for few months till I could find some time to debug this. After getting some hints from few online videos, I finally decided to find the issue myself as getting it fixed from Cube would be next to impossible considering my geography.
It appeared that most common issue with such symptoms was power related issue. I could not find any short circuits initially. But then noticed using multimeter that the one of the eeprom and display lvds chips were not getting any power. Then traced the back to find the Mosfet powering them and voila the mosfet had a open drain. The mosfet has “R1” labelled on it. After some digging found out that Mosfet to be CJ3401. Since I did not have it handy, I just removed the mosfet and shorted the source and the drain pins of the pads till I get the mosfet sourced(utsource seem to stock them).
Assembled everything back again, prayed a bit and moment of truth, clicked the power button. Voila! tablet booted successfully into windows. Was very happy!!!
I have benchmarks running for an hour now and everything is going on smoothly so far.
Below some pictures. The one on the left is what I fixed and one on right(same mosfet CJ3401) also looks faulty and usb otg is not working yet. So I am assuming it is the cause. Will try to fix it when I source the MOSFET.
Cheers!
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