My switch (working normally) had a broken FPC for the sd card. After swapping it (used heat gun from bellow, didn’t hit any capacitors while changing) it shows no sign of life.
Plugging USB-C cable gets a 4V reading on batter connector.
Battery also has 4V voltage drop disconnected, so its good.
No shorts on M92, BQ24, or pi3.
I made sure the connector was placed properly. I took it out again in case that was the problem.
No video nor backlight, no sound, nothing. Visually can’t see what could have been blown. I only worked around the SD connector.
Would appreciate any help diagnosing or fixing this issue, as I’m a newbie in schematics.
Hello friend, in the load IC line, 15V must be present, but in the video chip, 3.3V must be present, and in the load IC capacitors, 3.3V must be present. These are the vols that the capacitor must have. lcd backlight ic at 4.5 check these vols if they are present because if they are not there it will not turn on
Thanks. I think I ended up making things worse. When checking for the voltage, with charger plugged / battery unplugged, I had 15v on the fuse above the usc-b port, on the capacitor above it too, and on one of the BQ capacitors ( the others had 4.6V) . Plugged with battery but no charger, it was 0.
After I unplugged the battery and plugged the charger back on, I accidentally shorted the fuse, i think ( a spark came out, I think I touched both the usc-b port (ground) and the 15v fuse). I checked again and it was still giving 15v in both sides, so I think it was alright. Checking the BQ capacitors one more time I think I shorted something again, a spark came around the capacitors and the fuse. Now the fuse gives 0V. I’ll stop messing around and see if someone is willing to repair it.