A2338 820-02773 - External Display Not Working

[RepairxD]

Issue: No output on External Display

UF790
Previously there was output on Pin 6 but now there is none.
Pin 1 - 0.370 - 3.8v on
Pin 2 - 0.536 - 1.8v on
Pin 3 - 0.527 - 1.8v on

6 - 0.539
7 - 0.540
8 - 0.539

Thunderbolt
PP0V805_USBC_FIXED - 0V
PP1V2_USBC_VDDIO - 0V
PP0V855_USBC_CIO - 0V

I believe the UF790 is faulty but I do not currently have a replacement to test. Is there something else I should be checking? Sorry, I know you might need a lot more information but I'm not sure which information will be relevant just yet.

 

[2informaticos]

Tried both ports on both possible connection ways (4 tries)?

If at least one of inputs is high, UF790 should release the outputs.
USB pendrive is detected?
If not, check 5V_S2_UPC presence.

 

[RepairxD]

Yes tried all 4 tries, not working,
and i am getting 1.8 volt on UPC0_ATCRTMR01_PWR_EN & UPC1_ATCRTMR01_PWR_EN.
and before i am getting 3.3 volt on pin 6 of UF790 (ATC01_VDDCIO_VR_EN).
but now no any output on pin 6,7,8 on UF790. external mouse and keyboard working fine.

 

[2informaticos]

Resolder/change UF790...

 

[RepairxD]

Resolder/change UF790...

Spare not available..can i bypass it ?

 

[2informaticos]

I don't think to be possible.
It has a timing diagram, which may be critical.