820--01598 no display

Hi , ive got an 820--01598 with no display, no signs of any liquid spill at all , board is very clean , ive tried 2 new screens . I can hear the charger being put in and out . not sure what voltages i should have without the screen connected but i have 5V on PP5V_SOSW_LCD_R and 0v ON PP3V3_SOSW_LCD , PP3V3_G3H_RTC is present at U8501 but LCD_PWR_SLEW_3V3 is missing (diode reading 698) along with PANEL_P3V3_EN (diode reading 555), should these voltages be there without a screen connected on this model .
 

2informaticos

Administrator
Staff member
You must check voltages on LCD connector when the screen is connected.
Some voltages appear in the first seconds without screen, but will disappear soon, as LCD display is not recognized.

Check if you have USB activity.
 
mmm didnt think of that , thought if i could hear the charger being plugged in and out the board was powering on but yep no usb activity , also cant find power rails page on the schematic , has it been replaced by the functional test points page ??
 
Last edited:

2informaticos

Administrator
Staff member
For some reason board gets stuck.
No reason to search for video in such case.

Try DFU revive/restore...
 
Hi , never knew about dfu mode , ok ive got the laptop saying its in dfu mode , i go to actions but "restore" is greyed out , i did notice a padlock icon before the dfu picture , now this laptop belongs to a bank so im guessing it has security on it , could that be the reason i cant select restore , if so is there a way round it
 
ok just watched louis video on it and realise i have to double click the dfu box , went through the restore option and it looked like it went through its steps and finished but i still have nothing , any more suggestions ?
 
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