13" Macbook intermittent backlight issue

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13" white macbook. Refurb from Apple in 2008. Intermittent backlight.

The backlight will cut in and out as I adjust the angle of the screen.
Will sometimes cut out when the screen and the macbook are perfectly still.

Actions to date
Top case disassembly, removed the bevel from around the screen and the white plastic 'C section' cover below the screen that protects the backlight.

Doing this revealed the following...

On the left hand hinge/bracket there are what seem to be 2 sets of cables running through. I believe one is called the LVDS cable? That doesn't seem to be the problem. My problem is with the other set, the two cables that are thinner. From memory one is grey and one is black. It seems that through the action of 2 years of the screen moving up and down the wires have been gradually chewed/twisted. A little of the wire was exposed due to the insulation being chewed away.

My first attempt to insulate the wires seemed to fix the problem and for 2 weeks things went back to normal. Then the problem returned and continued to get worse. I took it apart again to check my work and my insulation was still in place so I'm beginning to think that the wire/cable is snapping inside due to the movement and will need to be replaced.

Only problem is that I can find no reference to these cables online. Can anyone help me with this issue by telling me what these cables are called and if and where I can buy them to replace?

Thank you, this forum is awesome.
 

chscag

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I believe (can't be 100% certain) that these are the cables from the inverter (supplies AC power to the backlight). Try going to the iFixit: The free repair manual web site and look up the step by step instructions for changing out the display. You may be able to identify the cables and order from them (if they have them).

Once you properly identify which cables you need, you may be able to order them from other sources: PowerbookMedic. Or maybe if you're lucky be able to find a set on eBay.
 
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Thank you for that lead. It has given me some fresh direction.

The two smaller leads that concerned me turn out to be the ones that connect to the airport card, therefore having no bearing whatsoever on my backlight problem.

So it cancels that out but leaves me with the question of where could the problem now lie. On the same left hinge with the inverter cable? or could the problem be on the right hinge...are any of the cables/leads on that side related to the backlight in anyway?

Thanks again for the useful post!
 

chscag

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The two smaller leads are probably the antenna wires that loop thru the back side of the LCD and attach to the airport card. They would have nothing to do with the problem - however, don't mess with them as that could degrade any wireless signals.

You're probably going to have to hunt around a bit thru the hinge areas and see where the cables go to. The LVDS cable is very important as it carries the video signals to the LCD. If that cable is bad, you'll have to replace the entire display assembly as Apple nor anyone else sell it as a stand alone part.

Sorry I can't be of more help - about the only thing I can advise is to use the sites I gave you in my other reply. They both have good break downs of what and where everything is. Just be careful not to break something else while you're trouble shooting.
 
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macbook MB881ll/a

i have a macbook a1181-MB881LL/a

and i am also having the intermittent backlight issue

when i open the screen to a certain position it is fine and others it is verry dim..

i am a apple tech so if any suggestions i will be able to do so.

so far i have taken the computer appart taken the bezel off and the c chanel and taken the inverter board out and inspected.. it looks fine i have taken thee inverter cable out and inspected visually it all looks fine and i put it all back together.. and it worked fine for a month or so.. but then today it started doign it again.. i would take it appart again but i do not want a temoporary fix i want it o be done.. i do not haev a full bank account so i do not want to just buy parts and slap them in and hope it fixes it i would like any and all input on this matter..

sorry for the mis typed words i am in quite a hurry to get this typed so i can get feedback asap

Josh,

early 09 macbook a1181-MB881LL/a
 
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I thought all Macs have been using LED backlights since late 2008. If that's the case then I don't see why there'd be an inverter...

The ifixit photos show just one cable that goes to the LCD panel - they make no mention (at least that I saw) of any additional connections.
 

chscag

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He has a MacBook. You may be thinking of when Apple began using LEDs for the backlight on certain MBP models. The lesser expensive MacBook still used the CCFD backlight so would need an inverter to power it.
 
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I had the very same problem and, for some reason, resetting the PRAM on my Macbook sorted it out!
 
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Backlight issue

My problem is similar to the above...

If I bring the brightness to 0 then go up 1 level, it works. Then it just shuts down the display from time to time. I have to go back to 0 then up one level again.

I'll get a day of functionality from it or maybe a week.

I noticed that when my hard drive started to approach its max capacity, it would act up more.

I now have 70 gigs of free space and I'm back to square one.

Now I'm lucky if it gives me an hour of functionality.

I have replaced the screen back in 2009 myself & never had a problem til about 6 months ago..

I reset the pram.

I'm preparing to replace to pram battery, the inverter, the logic board, the LCD panel & the inverter cable... Just to be on the safe side.

Did I miss anything?
 

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