820-3115 b screen white

[andrespi]

this macbook this macbook has white screens, I tested with good screen, problem persists, memory ram good, slots ram good, not video external.not usb activity.I only have ram memory, fan and screen connected what measurements do i do?

 

[brunomotter]

Does it chime?

 

[andrespi]

not chime.

 

[brunomotter]

try flashing bios first

 

[andrespi]

not

 

[brunomotter]

Reset SMC and PRAM, see if it chimes

 

[andrespi]

no reset pram, yes reset smc, persist problem

 

[2informaticos]

Put back original BIOS.
If pure white, missing 3v at TFT matrix.
Voltage at pins 2/3 of J9000?
If no voltage, check L9004 first.

 

[andrespi]

Are these measurements l9004 and pins 2/3 with the screen connected?
you have bios original functional?

 

[2informaticos]

Do NOT touch the BIOS again; write back the original.

Of course, LCD must be connected when measure there.

 

[andrespi]

excuse me, I don't understand " Do NOT touch the BIOS again; write back the original" what do you mean "write back the original"? It refers to erase bios that it has and write another file good of the same board reference?

 

[2informaticos]

You don't have a BIOS problem; original board BIOS is good, put it back.

 

[andrespi]

l9004=3.2v pin2/3=3.2v

 

[2informaticos]

Sorry, didn't pay full atentiuon to first post.
I just saw you've said no USB activity, nor external video.
Very strange to get backlight in this case.

Post CPU core voltage after 10s.
Try one good RAM module at time, each slot separately.

 

[andrespi]

Vcore=0.78v l7520,l7510 with module ram good each slot separately
flash bios?

 

[2informaticos]

With 0.78V board boots.
Are you sure there is no USB activity?
Did you check both ports?
If yes, try BIOS...

 

[andrespi]

yes both ports, you have file bios good for this board

 

[2informaticos]

820-3115-B DTY3 Clean ME - OK.rar

drive.google.com

 

[andrespi]

yes it is bios, you are genius!!