Technical Support Toshiba Satellite C855-2CK Black Screen

[Nikosz]

Hello.
i have this model with motherboard PLF/PLR/CSF/CSR DSC MB Rev:2.1
When I press the button to start it shows me a black screen and the fan turns on.
I tried with a new bios, ram, cpu but it did not work.
With external monitor is not working
there is some idea of what might be wrong?
thank you

 

[Ahmad Safari]

HI
It may be from the graphics
It is better to rebal the chip

 

[Nikosz]

hi,
I replaced the chip with the same results

 

[Nikosz]

UMA for this model or Satellite C850?

 

[Patrick Ribbsaeter]

UMA for this model or Satellite C850?

Did u check the working conditions for RAM IC? VDDQ, VTT etc...

 

[Nikosz]

yes, all measurements are correct

 

[Ahmad Safari]

Test this method

 

[Nikosz]

Thanks for the help. what method should I follow?

 

[Patrick Ribbsaeter]

Thanks for the help. what method should I follow?

U can start with posting what measurements you have done…

 

[Ahmad Safari]

Thanks for the help. what method should I follow?

Extract the attached file and move the parts according to the image.

 

[Patrick Ribbsaeter]

Thanks for the help. what method should I follow?

Have you chcked display connector,voltage and diode mode readings on pins?
Have u checked LPC_Frame? Diode mode readings?
Have u checked AD Line (0-3) for the display?

U need display before backlight. So focus on fixing display first.

 

[Nikosz]

hello, LagaDatorUmea thanks for your help. I replaced the chip with a new and now working.
one Satellite C850 and one Satellite C855 fixed with new chip

 

[Patrick Ribbsaeter]

hello, LagaDatorUmea thanks for your help. I replaced the chip with a new and now working.
one Satellite C850 and one Satellite C855 fixed with new chip

That's great news. Which chip did u replace? So other members can learn from this case.. Thank you

 

[Nikosz]

For Satellite C850 I replaced the bga 216-0833000
For Satellite C855 I replaced the bga 216-0810028
both with new. with used did not work