820-00875-01 Spill no screen

[2informaticos]

First of all, welcome to the forum!

5% tollerance is good enough.
Even 10% shouldn't be a problem.
Get resistors book, without caps.
Mixed resistors + caps books are bulshits.
Just try to get as many resistance values possible in the same book.

R8402 value is not critical.
There will work 47K, as even 20K, or 75K.

Try to understand the function of a component in the schematic.
Then is easy to find a replacement.

If Caps Lock light doesn't react, there should be something more than backlight problem.
Liquid spill on backlight area is very dangerous, as can cause leakage from high voltage to a data line connected to CPU.

Post PPVCCCPU_S0G in the first seconds and also when power consumption drops to 300mA.

 

[jacekelgda]

Thanks for warm welcome and quick reply which is already helping.

0.92V and then 0.73V

I measured on C101K Pin 1

 

[2informaticos]

CPU core voltage looks like board boots.
Caps Lock reacts?

 

[jacekelgda]

I will connect to top case and check again. Just need to figure out which connector is for keyboard.

 

[jacekelgda]

wow, it actually just missing backlight now ... it's booting and shows login screen just missing backlight

 

[2informaticos]

Check voltage on both sides of D8410.

 

[jacekelgda]

0.008 so I think it's not there? Keep in mind I still have not soldered the R8402 so it's missing from the board. I also might have damaged the pad from under R8402 ( pin 2 ) - is it enough to run a wire from the probe which is just near it ?

 

[2informaticos]

Solder 39-68K in place of R8402.
Be sure to make good contact with pin 11/U8400.

 

[jacekelgda]

>Be sure to make good contact with pin 11/U8400.

How do I check that ? There seem to be no probe points for this pin and it's under the chip.

 

[2informaticos]

Not BGA chip, pins and traces easy available...

 

[jacekelgda]

true, I am able to get to that pin with some tool improv. What worries me is that the broken pad seems to be going trough the board on to the other side, is that correct ? Seems like almost impossible to solder to whatever is left in there

 

[jacekelgda]

I actually managed to solder it somehow. Now the R8402 is back in the circut.

 

[jacekelgda]

D8410 0.0053V on pin 1
0.0005 on pin 2

 

[2informaticos]

Are these values, voltage, or diode mode???

 

[jacekelgda]

voltage

 

[jacekelgda]

hm, 0.012 now on pin 1

 

[jacekelgda]

what should be the voltage in there ?

 

[jacekelgda]

C8442 is actually missing from the board, I can see it in the schematics but not on the board. Looks like an important component