KC Micro Tronix
Member
I am not sure of the history on this board. I can tell where someone else has tried to work on it before me so it's a basket case.
PP3V3_G3H was at 0.0v when I started. Located a bad cap C6991. Was kind of tricky to find. The resistance at the output of D6905 was 25 ohm, then 300 ohm. and I new there were only like three possible caps. It would not show up on thermal. So I tried C691 first and it was my culprate. Then after that I had to replace D6905 because the voltage drop across it was almost 2 volts. ( I have seen this a few times now with one of those three caps biting it)
So now the PP3V3_G3H supply is good and I have 3.4V at both the USB chips.
I have tried each chip using top and bottom usb ports and could see each one in thermal corresponding to it's port. The thermal signature is normal compared to my answer key board. It is now pulling 0.03A constant but no hot spots found. Neither one will give me 20v.
What else is required to get to 20v from the charger?
PP3V3_G3H was at 0.0v when I started. Located a bad cap C6991. Was kind of tricky to find. The resistance at the output of D6905 was 25 ohm, then 300 ohm. and I new there were only like three possible caps. It would not show up on thermal. So I tried C691 first and it was my culprate. Then after that I had to replace D6905 because the voltage drop across it was almost 2 volts. ( I have seen this a few times now with one of those three caps biting it)
So now the PP3V3_G3H supply is good and I have 3.4V at both the USB chips.
I have tried each chip using top and bottom usb ports and could see each one in thermal corresponding to it's port. The thermal signature is normal compared to my answer key board. It is now pulling 0.03A constant but no hot spots found. Neither one will give me 20v.
What else is required to get to 20v from the charger?
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