820 4924, no backlight

[Noguinfor]

Hey guys,
this one don't have any signals off liquid or corrosion!!
I have - 0V on pin1 J8300 and 0V at L8300.
already replace a LVDS cable for a new one = same history!

I already did a research here in the forum but did not clarify my doubt!

I have 3 macs 2013-2014 same model for repair and i already test 2 off them on this board (2015) and i can see the image with a flash light! But with original one i can't get precession if it has an image without backlight because the screen is very dirty (tipical problem on this models).

my question is if i test the board 820 4924 (2015) on mac 2014 it's normally don't get backlight?? I'm a little confused because some time ago i think to do this test and the backlight work's but with a 4-5 sec delay! but i'm not sure! for otherwise i see some topics on forum that say it's not compatibility!

thanks

 

[Alan.L]

Its usually the pin1 on these. Diode mode on pin1?

You cant use 2014 screen on a 2015 logic board. It?s needs to be the same year. I suggest you order a 2015 cracked screen from ebay for testing.

 

[Noguinfor]

Thanks Alan. i have 3 macs 2014 for repair! no one is 2015! =(

I think on this one it's the LCD fucked!

Diode mode one pin 1 with or without LCD connected = 1.165v

 

[2informaticos]

You can't be sure about backlight presence if you don't have the correct screen.
You can try with 2014 model and give it 1 min, to enter OSX and see if backlight appears.

However, if you get image with other screen, means L8300 voltage is present, and maintained; DP_INT_HPD is high.
You told no voltage at L8300 with original screen; that is problem.
You must get voltage there, in the first few seconds, even no screen connected.So seems that oeiginal screen is bad.
You should get DP_INT_HPD high with it, when L8300 has voltage...

 

[JohnB8812]

No. You MUST use a 2015 screen on these 2014 will always give no BKLT.