Why doesn't replacing inverter fix the backlight?

Question

MacBook

Repair guides for the MacBook.

3786 Questions View all

rbrunner @rbrunner5090

Rep: 23

2

1

Posted: Dec 6, 2011

Options

Why doesn't replacing inverter fix the backlight?

Hi,

My wife's Core 2 Duo Macbook recently started having backlight problems. The light will stay on for a few seconds to minutes after waking the computer up, then shuts off. Since it shuts off without moving the screen, I thought it was probably an inverter problem, not the cable. So I ordered the part here and did the replacement.

Unfortunately, after re-assembling the computer, I still have the same problem. Is there some other explanation for my symptoms? Possibilities include:

The inverter cable is bad (but why does it fail even when I don't move the computer?)
The replacement inverter is also bad

Any other explanations or suggestions on what to do now?

Robert

Answered! View the answer I have this problem too

Is this a good question?

Yes No

Score 1

Add a comment

2 Answers

Chosen Solution

ABCellars @abcellars70961

Rep: 26.3k

Suo Motu LLC

152

71

50

Posted: Dec 6, 2011

Options

Robert, I checked your profile there is no reference to another question asked here. It seems you researched the problem and determined that the inverter was the cause - Actually a very good analogy from the information given.

Your problem could be:

1) The inverter cable.

2) The backlight CCFL bulb.

3) On the motherboard.

If you own or have access to a multimeter/multitester (An analog one with the needle, is best for testing internal breaks in wires. The digital ones have slow reaction time.) you can test the integrity of the inverter cable with a continuity test while moving the wires around. If the needle sweeps hard at any point the cable could be the cause. By doing this you can determine if this part is the problem or not. Many people would frown upon this suggestion but, you can purchase a meter such as this and return it to the store after your minute with it is done. Don't take it back just yet, we might need it for another minute to yet to test voltages.

We need to know more things about this as we don't have physical access to the machine in question. Is there a red/pink/orange hue to the screen when it is lit - "especially just prior to it going dark"? Is there any flickering to the screen - again, "especially just prior to the screen going dark"? Is there any humming noise coming from the lower part of the screen - again....." "? Has this system ever experienced any liquid damage? What country is this laptop in? Please give us the last 3 characters of your serial number so we can determine your exact machine. If there is any further information you can think to add, please do so.

Was this answer helpful?

Yes No

Score 3

1 Comment:

Well, I do have a DMM, but not an analog multimeter. There's no noticeable color change, and there's no flickering or humming that I've noticed. If I open the lid, then leave the computer undisturbed, it reliably shuts off after a few minutes, which makes it seem unlikely to me that its a mechanical failure in the cable.

At this point I lack the enthusiasm to spend another 3 hours disassembling the laptop to do more testing, so I'm going to hook up an external screen and use it as my home server (to replace my 2004 PB G4.)

Jan 31, 2012 by rbrunner

Add a comment

Well, I do have a DMM, but not an analog multimeter. There's no noticeable color change, and there's no flickering or humming that I've noticed. If I open the lid, then leave the computer undisturbed, it reliably shuts off after a few minutes, which makes it seem unlikely to me that its a mechanical failure in the cable.

At this point I lack the enthusiasm to spend another 3 hours disassembling the laptop to do more testing, so I'm going to hook up an external screen and use it as my home server (to replace my 2004 PB G4.) — rbrunner