820-2915 no image no backlight

[donnos]

Got a 2915 with no image no backlight no external display. my guess is the GFX is dying/dead, and if its not it will soon be anyway, so wanting to try a Gmux flash for the first time, getting this error on lattice programmer below: so my guess is that the jtag scan came up empty because it failed to read U9600?

initially i measured that i didn't have pp3v3_sw_lcd and i had lcd_pwr_en and GPUvcore_EN and lazy to go on troubleshooting. should i replace u9600? if yes can it be from anyboard? if no what can i do next

Device#1 LFXP2-5E: Failed to verify the ID
(Expected: 0x01299043 Read: 0x00000000).

 

[2informaticos]

Did you remove L2406, or R2415?
Before connecting Lattice Diamond programmer...

You also must remove one of R8904/11, before starting the machine; once GMUX has been reflashed.

 

[donnos]

Thanks! this helped me

 

[donnos]

okay, using back the same thread as i just received another mac same model which does this.
Boots up apple logo with spinning wheel, about 15 seconds later, shuts down. but stays on when no HDD is plugged in. I read that this is the classic bad GPU issue on this model
Would DeMux solve this issue?

 

[2informaticos]

As simple as try it.

I suppose machine stays on without HDD because doesn't try to load the GPU driver.
You can try with Linux/Windows Live USB.