820-00281: No image on display. External works

Hello gents.

Got a board that originally came in for power failure. Found two caps that were lifted off their pads. This restore power once resoldered. But I?m not getting any image on the display. I do however get video via the usb-c to hdmi to external display

I?ve got the below measurements:


I?m waiting on a donor board to arrive and I was going to replace U9800, but wanted to see if you all had any other suggestions. Thanks.


Staff member
Any liquid sign on backlight area, or LCD connector?
Do you get image, only missing backlight?

Check in the first moments if U8500/01 get output voltage; at least 1-2s pulse...
Sorry for the late response

U8500/01 is 5v
U8500/05 is 5v

No image on the screen at all.

And yes, known good screen. Confirmed with another board that the screen was good.


Staff member
"U8500/01 is 5v
U8500/05 is 5v"
I do NOT really know how to interpret this...
U8501 doesn't have any pin connected to 5V!!!

BTW, U8500/01 means U8500 AND U8501...
Both chips have the output on pin 5.
Yeah was wondering if it was a typo as pin 1 of u8500 was an input pin hence why I included pin 5s reading. Sorry bout that.

Anyway, U8501 pin5 is 3.3v
U8500 pin5 is 5v
Yes they are all stable and all measurements were taken with the display connected. I?ll get the measurement later today, running out of town for a bit.
So decided to check in diode mode the values of all the pins on J8500, found out that U9850 that I had installed was bad. So ordered replacement from china and board now feeding image to display. Thanks guys for the assist again. This board is now fixed.