820-2879 green light, fan spin, no chime

[ajdoc]

Got 820-2879 with green light.
Wont auto turn on.

When I short WS_KBD_ONOFF_L with ground got fan spin but no chime, no image.

VCORE 0.9V

Any idea?

 

[dukefawks]

These never auto power on.
Resistance to GND on 3V42 rail? USB mouse lighting up? 0.9V on Vcore would indicate the board is POSTing. Vcore starts at 1.1V and then drops to 0.9V, check that too.

 

[ajdoc]

Resistance to GND on pp3V42_G3H is 22.15k
USB mouse light - yes
Vcore 1.1V then drop to 0.9V

Got chime now (test speaker was broken) but there is just backlight and no image.
Same issue with new LCD/LCD cable.

 

[dukefawks]

Check all LVDS lines on diode mode. Inspect connector for damage and missing coils in the LVDS data lines. L9080 is a common suspect.

 

[ajdoc]

L9080 was fine. Replaced LVDS connector and got image so thats fixed but now got another issue.

Wont load the system. It freeze during boot on spinning circle or progress bar.
I tested with 10.6.8, 10.9.5 and with 10.11.6.
Only sometimes desktop on 10.6.8 was loaded but frozen (checked with USB mouse/keyboard and system was frozen)
Same issue when boot via SATA, USB or FireWire.

Checked with 3 RAM modules.

Camera, trackpad, keyboard, DVD drive was disconnected - same thing if there are connected.
Any idea?

 

[ALB-Repairs]

What speed is your ram.
a 2879 would require PC3-8500, Sound like you are use 1333mhz modules which will cause no boot/spinning progress bar for ever and ever.