I replaced the LCD, but the backlight turns off after 2 seconds?

Question

MacBook Core Duo

Mediados de 2006 / número de modelo A1181 / carcasa negra o blanca / procesador Intel Core Duo de 1,83 o 2,0 GHz.

Preguntas 418 Ver todo

Roy @roy90773

Rep: 65

2

1

Publicado: 25 de jun. de 2010

Opciones

I replaced the LCD, but the backlight turns off after 2 seconds?

Did I mess up the connection to the inverter? The screen looks great for about 2 seconds at start up, after waking from sleep (also for 2 seconds), and when I take the brightness from all the way down to anything up. But it never stays on for more than a couple seconds. I can still see images on the screen it's just not illuminated.

A magnet did drop out while I was re-installing the LCD and I can't tell where it is supposed to go. Does it trigger a control to keep the backlight on? It is not one of the 4 magnets in the top corners of the LCD case. Thanks for any help you can give!

Contestado! Ver respuesta Yo también tengo este problema

Es esta una buena pregunta?

Sí No

Puntuación 2

2 comentarios

+ well stated question

25 de jun. de 2010 - de mayer

A quick follow up. The replacement LCD must have been a refurb. The wires coming out of it to plug into the inverter had been repaired. I sent the screen back and ordered another from a different vendor. This one worked perfectly. It must have been the connection to the inverter! Thanks for all the help and advice

28 de jul. de 2010 - de Roy

Agregar un comentario

4 Respuestas

Solución Elegida

markus weiher @markusweiher

Rep: 35.1mil

140

71

53

Publicado: 25 de jun. de 2010

Opciones

there are most likely 3 possible problems

the inverter cable is scuffed or clamped
the backlight tubes (CCFL) are defective
the inverter is faulty

i marked the magnet position on the picture, but it has nothing to do with the backlight problem. did you change the inverter too ?

check the position of the inverter cable

Fue útil esta respuesta?

Sí No

Puntuación 6

5 comentarios:

Good Pics +

25 de jun. de 2010 - de Majesty

+ nice answer

25 de jun. de 2010 - de mayer

I got the magnet back in place, but, like you said no effect on the backlight. I did not change the inverter, and I didn't take the case apart to get into the area you showed. I only removed the LCD frame from the enclosure. Could be a cable, I may try to put the old one back in to see if it acts the same way. The old one was working fine apart from the cracks.

It's strange that I can get it to come on repeatedly by changing the brightness from 0 to 1, but it goes off after 2 seconds! It seems as though everything can function, but something is sending a signal to turn the backlight off.

25 de jun. de 2010 - de Roy

Took it by the Apple store to talk to a "Genius" He agreed it was somehow related to the inverter. Thanks for your help!

25 de jun. de 2010 - de Roy

since you didn't change those parts - it's possible that the ccfl tubes inside the lcd are bad. good idea to change the lcd back, if the backlight works normal, the ccfl tubes are bad - they can be replaced - but you have to be careful - they are very fragile

25 de jun. de 2010 - de markus weiher

Agregar un comentario

A quick follow up. The replacement LCD must have been a refurb. The wires coming out of it to plug into the inverter had been repaired. I sent the screen back and ordered another from a different vendor. This one worked perfectly. It must have been the connection to the inverter! Thanks for all the help and advice — Roy
I got the magnet back in place, but, like you said no effect on the backlight. I did not change the inverter, and I didn't take the case apart to get into the area you showed. I only removed the LCD frame from the enclosure. Could be a cable, I may try to put the old one back in to see if it acts the same way. The old one was working fine apart from the cracks.

It's strange that I can get it to come on repeatedly by changing the brightness from 0 to 1, but it goes off after 2 seconds! It seems as though everything can function, but something is sending a signal to turn the backlight off. — Roy
Took it by the Apple store to talk to a "Genius" He agreed it was somehow related to the inverter. Thanks for your help! — Roy
since you didn't change those parts - it's possible that the ccfl tubes inside the lcd are bad. good idea to change the lcd back, if the backlight works normal, the ccfl tubes are bad - they can be replaced - but you have to be careful - they are very fragile — markus weiher

lemerise @lemerise Rep: 37.6mil 315 66 72 · Answer 1 · 2010-06-25T16:16:53-07:00

lemerise @lemerise

Rep: 37.6mil

315

66

72

Publicado: 25 de jun. de 2010

Opciones

If the display lights for 2 seconds then the backlight lamp should be working. I would suspect a bad inverter board or a bad logic board. Any liquid spilled on the MB ?

Fue útil esta respuesta?

Sí No

Puntuación 0

Agregar un comentario

dadioh @dadioh Rep: 221 7 4 · Answer 2 · 2010-07-28T10:11:00-07:00

dadioh @dadioh

Rep: 221

7

4

Publicado: 28 de jul. de 2010

Opciones

When it dims do you see the screen display the dimming logo (the one that hows the brightness sun logo and the bars decreasing below it? The reason I ask is if the key on the keyboard that controls brightness is "stuck" then it would continuously dim the display. You could verify by disconnecting the built in keyboard and using an external keyboard.

Just a thought...

Fue útil esta respuesta?

Sí No

Puntuación 0

2 comentarios:

These keys shouldn't be active just after startup.

28 de jul. de 2010 - de remacberlin

Yes I did see the icon, turns out it was a problem with the wires and/or connector to the inverter. thanks

28 de jul. de 2010 - de Roy

Agregar un comentario