A1706 820-00923-A no image

[hgoncalves]

Hi,

I have an A1706 820-00923-A with no imagem on the internal display, but it has image on external display.

Already tried known good display and cable, but same result.

DFR_DISP_PWR_EN = 3.4V

EDP_PANEL_PWR_EN = 3.3V

PP5V_S0SW_LCD = 5.1V

PANEL_P5V_EN = 3.3V

PP3V3_S0SW_LCD = 3.3V

PPVOUT_S0_LCDBKLT = 0V, and 0.051 on diode reading

PPVIN_SW_LCDBKLT_SW = 0V and 0.830 on diode reading

Can you help?

 

[2informaticos]

Did you check diode mode to ground on J8500?
Pay atention to pins 1 & 3.

 

[hgoncalves]

Hi,

I forgoted it...

Everything seams OK on J8500, except PPVOUT_S0_LCDBKLT that has 0.066 on diode to ground (not sure if it is a normal value cause it is a high voltage line).

Pins 1 and 3 have 0.261 diode to ground

I notice that when reading diode on D8410, when I reverse the multimeter tips, the current flows both ways. Already replaced the diode, and apparently it only happens when soldered to the board. I don't think it should, correct?

 

[2informaticos]

0.066 is very low there; was this with LCD connected?
If not, probably bad filter cap on backlight output rail.

 

[hgoncalves]

It was a bad cap.

TKS!