[SOLVED]820-3536 Power button not working

[Fizzl92]

This 820-3536 was waterdamaged. The board itself had no water on it. I replaced the keyboard (after shorting R5115 it turned on) and cleaned the board to be sure i did not miss any water. Now it works except the power button. The button turns the machine just some rare times on but mostly it has no function... SMC_ONOFF_L jumps from 3.42V to 3.25V when i press the power button. I am not sure whats the issue except its the SMC again...

 

[smiba]

Check the resistor from the keyboard to this line

Possibly just a bad keyboard though

 

[aprendiz]

Bad keyboard...

 

[dukefawks]

Probably the flatcable/connector or touchpad. Or a dead keyboard.

 

[Fizzl92]

I tried another keyboard and still the same. If i short the pads of R5116 it works fine. R4810 is 0.887K Ohm. I also checked the Trackpad, cable and connector. All looks fine there and with the Trackpad unplugged its still the same issue.

 

[dukefawks]

Voltage on R4810 pin 2 when power button pressed. If it does not go down it is either a bad keyboard or connector.

 

[Fizzl92]

No Title

Voltage on Pin 5 of J4813 goes down from 3.42V to 3.22V if i press the Button. If i hold it it stays at 3.22V. I also tried another new keyboard and still the same. Connector looks fine to me

 

[dukefawks]

Then there is either a very strong pull up on there or both keyboards are fucked. Measure resistance from pin 5 to 3V42 to determine the pull up resistor value.

 

[Fizzl92]

Resistance between Pin 4 and 5 of J4813 is 25Ohm. I ordered another keyboard to be sure.

 

[dukefawks]

There is your problem, there is a 25 ohm pull up. So short in KBC connector between pins 4 and 5.

 

[Fizzl92]

Yeah that was it. Now its back up to 10k Ohm and works fine. Thank you again very much for the great support!