hi friends.
I just have an 820-3787 here it had a hole in the board near u7100 and no power on
I replaced U7100 and soldered the missing traces. After that it worked, Trackpad working, keyboard wrote what it want. Then with a new Akku I noticed that It consumed 4-6A, after that I limited the curent to 3,5
I found that R7121/22 are bad. After replacing current was normal (about 3.4A not rising anymore)
Now I found that the damaged U7100 burned a hole in the Keyboard cable until the metal of the keyboard.
So I replaced the keyboard. But still the same problem.
I tryed another mainboard in the same case, now keyboard and trackpad is working well.
I dont know why but the keyboard and trackpad is not working anymore.
I found on J4800 Pin 22 and 18 has power,
Pin 20 Z2_CLKIN nothing
So I checked U 4801 and found in diode mode Pin 23-28 nothing.
I replaced U4801, Diode mode all pins ok now.J4800 Pin 20 has clock now. But no trackpad ( I disconnected the keyboard and only try to get trackpad until now)
then I found in the forum that duke wrote U4801 needs only power and usb and as to show up in the osx. I tryed with a good mainboard first. internal keyboard and trackpad is shown up.
with the problem board it shows nothing. In diode mode I get on R4801/02 both sides the same reading (good and bad board)
R4801 has 3.13V, R4802 0V. On the good board it has 0V as well
The U4801 is programmed. I took it from a 820-3332. Pinout is the same. may be there is no comunication?
External keyboard and mouse is working good
Need some help please
I just have an 820-3787 here it had a hole in the board near u7100 and no power on
I replaced U7100 and soldered the missing traces. After that it worked, Trackpad working, keyboard wrote what it want. Then with a new Akku I noticed that It consumed 4-6A, after that I limited the curent to 3,5
I found that R7121/22 are bad. After replacing current was normal (about 3.4A not rising anymore)
Now I found that the damaged U7100 burned a hole in the Keyboard cable until the metal of the keyboard.
So I replaced the keyboard. But still the same problem.
I tryed another mainboard in the same case, now keyboard and trackpad is working well.
I dont know why but the keyboard and trackpad is not working anymore.
I found on J4800 Pin 22 and 18 has power,
Pin 20 Z2_CLKIN nothing
So I checked U 4801 and found in diode mode Pin 23-28 nothing.
I replaced U4801, Diode mode all pins ok now.J4800 Pin 20 has clock now. But no trackpad ( I disconnected the keyboard and only try to get trackpad until now)
then I found in the forum that duke wrote U4801 needs only power and usb and as to show up in the osx. I tryed with a good mainboard first. internal keyboard and trackpad is shown up.
with the problem board it shows nothing. In diode mode I get on R4801/02 both sides the same reading (good and bad board)
R4801 has 3.13V, R4802 0V. On the good board it has 0V as well
The U4801 is programmed. I took it from a 820-3332. Pinout is the same. may be there is no comunication?
External keyboard and mouse is working good
Need some help please
Attachments
Last edited: