820-00850 NO DISPLAY ON INTERNAL SCREEN

huzeafa

Member
good day guys, I hope all of you are well, please have got an issue with my 820-00850 , it does not display on the internal screen ,but displays fine on external monitor, I have swapped with a different screen cable, and screen but still no changes.

At U8510
EDP_PANEL_PWR_BUF_EN = 0.22
PP3V3_G3H_RTC. ==3.3V
EDP_PANEL_PWR_EN = 3.3V
EDP_PANEL_PWR_DLY_EN = 3.3V
PM_SLP_TIEOFF = 3.3V


At J8500
pin 1 EDP_INT_AUX_N = 0V
pin 2 GND
PIN 3 EDP_INT_AUX_P = 0V
PIN 4 EDP_PANEL_PWR_BUF_EN = 0.22
PIN 5 GND
PIN 6 DP_INT_HPD = 0V
PIN 7 EDP_INT_ML_N = 0V
PIN 8 GND
PIN 9 EDP_INT_ML_P = 0V
PIN 10 TP_LCD_IRQ_L = 0.019
PIN 11& 12 GND
PIN 13 EDP_INT_ML_N = 0.125
PIN 14 UNCONNECTED
PIN 15 EDP_INT_ML_P = 0.01
PIN 16 BKLT_PWM_MLB2TCON = 0V
PIN 17/18 GND
PIN 19 EDP_INT_ML_N = 0.1V
PIN 28 AND 30 I2C_TCON_SDA = 3.3V
PIN 34 I2C_ALS_SDA = 1.8V
PIN 44 PP3V3_S0SW_LCD = 3.3V
PIN 45 PP5V_S0SW_LCD = 5V
since I did not get 3.3V at EDP_PANEL_PWR_BUF_EN I replaced U8510 but no changes
please help.
 

2informaticos

Administrator
Staff member
Check diode mode to ground at EDP_PANEL_PWR_BUF_EN .
Be sure to have good solders at U8510.
Also check pin 12 voltage.
 

huzeafa

Member
I have re-soldered U8510 , but still get OL, I tried to also measure when the chip was off the board , and I still get OL, I will try another chip , one quick question, must it be from the same exact board even though 820-00239 uses the same ?
 
Top