820-3437b no thunderbolt

[TBFix]

There are no signs of spillage on the board I ran diagnostics and its failing for thunderbolt issues. There is no external output. Where to start troubleshooting this issue?

 

[2informaticos]

Check if TBT_A_HV_EN goes high when insert a thunderbolt device.
Be sure to have 3V at pin 20/J3200.
Also check if TBT_A_HPD reacts when plug in Thunderbolt.

 

[TBFix]

TBT_A_HV_EN does not change
pin 20/J3200 = 3v
TBT_A_HPD goes to 0.5v when I plug in Thunderbolt

 

[2informaticos]

Thunderbolt detection not working properly.
Did you try another device?

Do you get PP3V3_S4_TBTAPWR

 

[TBFix]

What should you get at TBT_A_HPD ? is that for detection?
PP3V3_S4_TBTAPWR is 3v

 

[2informaticos]

HPD= HotPlugDetect; it should go above 2V.

 

[TBFix]

Adapter is working as I have tested it on another board. U2800 faulty?

 

[2informaticos]

Check HPD level on the other board.
Compare voltage reaction on different signals.
Also search for differencies of diode mode readings between both boards.

 

[TBFix]

It not the same model board

 

[2informaticos]

Thunderbolt port should have the same pins.
Check the reaction voltage and diode mode at HPD pin...