No LCD display but backlight, sound, and touch work

Really hoping someone can help me out here. The LCD screen on my Switch is blank (no logo) when I boot but the backlight turns on and I can hear sounds when I touch the digitizer. I replaced the USB-C port on the switch and everything was working but I was concerned with the inner USB connections so I redid the port install. After that I was unable to see anything on the screen except for the backlight.

Trying to get to the bottom of the issue I’ve:

  • Checked all major caps and filters for shorts - multiple times and none that I could find
  • Checked for any missing/moved/damaged components
  • Removed the USB-C port in case there was some issue there
  • Tested with 2 other known good LCD screens
  • Tested with 2 other known good batteries
  • Checked LCD connector for damage a few times - it looks pristine
  • Plugged in the digitizer and speakers and was able to hear touch inputs

One of these two chipsets may be destroyed. M92T36 or P13USB

Spent some more time debugging this issue and I’m noticing there is no voltage in the caps near BD8316GWL (and about 1.8v if I remember correctly on test points to left of chip) when I turn it on and based on the datasheet for that part it seems like it should be getting between 2.5v - 5.5v.

I also checked the diode measurements against a diagram I found in another thread www.tronicsfixforum[.]com/uploads/db3735/original/2X/2/292248096c235419e6d4b3c99bfa73d278d0ef07.png and the right three components (directly above 8316) are giving me some high readings ~1800 instead of 708 and 700 - the rest of the measurements are good and verified on another board those 1800 readings are not supposed to be that high.

Does anyone know if that supply voltage to 8316 is an issue and where to start looking next? Thanks in advanced.

Thanks for the response. Is there a way to check before swapping them out? Seems a little odd I’d still be able to run everything except LCD and have no blown caps but I don’t know…

I wouldn’t worry about M92 and P13, as they cannot cause a screen issue. I would first check the LCD connector as it is very easy to bend the pins when inserting the cable. If the LCD cable and connector look fine then we should dig more into that circuit.

Thanks for the help! I looked under a microscope at all the pins and all of them look great (just double checked this as well). I also checked the diode measurements based on the image I linked to in here for each pin and was getting similar values.

Ok, so next I would check for the +5v, -5V and 1.8v enable signal as show in this picture.

That diagram is super helpful. I have 0v on both VOUT points. Enable lines are getting 1.8v and A1 is at 3.89v. Checked the diodes and they seem fine too. Seems to me that means 8316 should be replaced since I’m getting the enable signal and input voltage but no output?

Yeah, I think that’s what I would try.

I’ve ordered a replacement and I’ll report back once it arrives in a few days. Appreciate the help here.

Following as I have a similar issue. Vin @ 3.7v and enable voltage at 1.85V. I also have a diode blown, connected to A1, anyone have a part number for that little guy?

Thanks everyone.