Backlight dead, no brightness controls, LCD hardware OK
Hello,
I have a strange problem on my Macbook Pro.
The backlight is not working.
Everything else is Ok, external Display works fine.
Also I have backlight on that LCD when I connect it to another macbook pro.
I checked the inverter, the I/O Board and wiring.
Found the I/O board faulty (smd resistance dead) and replaced it.
Still, the backlight is dead. (from the beginning when I turn on the MBP)
What I found strange is, that also there is no backlight-control-symbol showing on the sreen when I push F1, F2 (I made sure that it is not Fn-F1, F2). Rest of the F keys are working as they should.
Can that really be a hardware fault? - I would at least expect showing up the backlight symbol on the screen.
The display is properly recognised in the properties as it should (about my mac).
Does anybody have an idea what I am probably missing? Is there probably some analysis program that might give more information?
Thanks for your help.
Kind regards,
cal
Is this a good question?
3 Comments
Do you mean the smd resistance on the logic board ? If so, do you get voltage at the smd resistance output after replacement cause the problem could be related to a faulty component located before the smd resistance ?
by lemerise
Hi,
thank you for the tips.
I performed the PRAM Reset and also the Target mode booting.
It did not help. Also the OS was installed completely freshly just before.
I have no backlight from the beginning of the booting - so I do not think it is an OSX problem.
What might be the critical hint is, that my brightness controls are not accessible - means that if I push the F1 or F2 keys, even the icon on the screen is not showing up. This is very strange isn't it?
May be someone has an insight into the system structure and can conclude on the faulty part. My conclusion would have been, that the display is not recogized properly and so it gives no control for brightness (like for external displays) - but the display is properly shown in the "About my mac"....
Suggestions are welcome....
Cheers, cal
by cal007
@Lemerise: it was afaukty SMD resistor on the I/O Board - I replaced the whole board. But this did not bring the backlight back. May be someone could instruct me how to measure the input voltage (4 wires).
Thanks.
Cal
by cal007