820-3476 no green light or ppbus_g3h

ytesfay80

Member
Dang. I don't have another retina mbp.
how can I connect an external lcd to thunderbolt? I tried connecting the computer to my tv with a thunderbolt to hdmi adapter i have but that didn't work since the PP15v_tbt and the other TBT rails aren't present anymore. It was present before I replaced that burned u7700 chip.
 
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dukefawks

Administrator
I have no idea any more. If you cannot rule out a defective LCD you can mess with the board all you want it is not going to work. This problem could now be the board or the LCD
 

ytesfay80

Member
Okay. Hopefully I can restore the thunderbolt rails so I can at least know that works. I am not getting PP15v_TBT and I traced that back to Q3005. I am not getting anything on TBT_A_HV_EN and that signal comes from U2800 which is covered with a shield.

Do you know what signal turns on the U2800 because maybe that is missing?
 
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