Macbook A1278 LCD backlight problem

[salawayon]

Macbook a1278 unibody, aluminum body... 3.3vdc is present at pin 2, 3 and 4, both at lcd connector and at main board connector.... Tried already replacing the lcd.... I need schematics for this one. Or anyone could share some infos on this problem.

Thanks....

[cyberhack]

Re: Macbook A1278 LCD backlight problem

here you go

[salawayon]

Re: Macbook A1278 LCD backlight problem

Thanks... But it's not the same with the board... BTW, it is a non-pro model. And the WLED DRIVER (APP_1A) chip doesn't have an input voltage.... Fuse is ok.

[cyberhack]

Re: Macbook A1278 LCD backlight problem

have a look at this link
http://forums.macrumors.com/showthread.php?t=972699
if not allowed please remove

[salawayon]

Re: Macbook A1278 LCD backlight problem

i've been reading that pages before i posted here for schematics.... i still didn't get the right schematics.... i'm on page 32 already...

[salawayon]

Re: Macbook A1278 LCD backlight problem

anyone could share? Macbook 13" unibody, aluminun case, non-pro version, schemaitcs is needed.

Thanks...

[spidey]

Re: Macbook A1278 LCD backlight problem

to get the right schematic you must supply the board code like 820-2530.

[salawayon]

Re: Macbook A1278 LCD backlight problem

Motherboard model: 820-2327-A

Thanks....

[spidey]

Re: Macbook A1278 LCD backlight problem

here it is.

[mamoime]

Re: Macbook A1278 LCD backlight problem

here you go

Hi,

Where can I download .brd files of other macbook mainboard to use with this software viewer?

Many thanks in advance

[dspok]

Re: Macbook A1278 LCD backlight problem

@salawayon
did you fixed it.
I have same problem. I want to figure out the location of LCD Backlight Driver.
Can anybody tell the exact location please.

[dellxps15]

Re: Macbook A1278 LCD backlight problem

what is macbook model ? 820-xxxx

[dspok]

Re: Macbook A1278 LCD backlight problem

@dellxps
I found it & measured 12.44v for backlight. Is it normal?
Can see apple logo but still no backlight.

[dellxps15]

Re: Macbook A1278 LCD backlight problem

edit: ok we are talking about a a1278.

edit2: 12.5volt on backlight fuse are ok. if you can try another lcd, and inspect if lcd cable is all ok.

[Macman1974]

Re: Macbook A1278 LCD backlight problem

Hi,

Where can I download .brd files of other macbook mainboard to use with this software viewer?

Many thanks in advance

Here you go hope this helps.

[BCConnectionLLC]

Re: Macbook A1278 LCD backlight problem

Get everything in one post

At the LVDS you have 12v on the PPVOUT_S0_LCDBKLT line?

IF YES

Sounds like your boost circuit isnt working

Start looking at U9701

What do you have on Pin 1, 2, and 3?

[saifi]

Re: Macbook A1278 LCD backlight problem

thanksssss