[mcarland]

Hello,

I have an iBook G3/600 with a display problem, and was wondering if someone could make a recommendation for a fix. I was thinking I need to replace the inverter cable, but my problem doesn't sound quite like the descriptions I've read about.

The hard drive had failed about two weeks ago, so I replaced that, which may have aggrevated this problem.

The problem is with the display backlight, it will jump up and down in brightness, sometimes dimming slightly, sometimes halfway, and sometimes completely. This will happen if the laptop is sitting on a table undisturbed. Adjusting the tilt of the monitor doesn't seem to affect it too much, it's not like it works or doesn't work at certain angles. When the backlight goes out, slightly torquing the front of the body of the computer, or the display, is the method that most often brings the display back. Also, most of the time it doesn't seem to just cut off and on, it slightly ramps, like it is dimming and undimming.

I have poked around at the cable as it goes past the hing and have not been able to get the display to falter. That and the angle of the display having little effect makes be believe a inverter cable will not resolve the problem. I checked the connection of that cable on the motherboard twice. I have reset the parameter ram. I have tried the reset button on the side of the machine while it was turned off.

Any suggestions? I would try the inverter cable for giggles if it wasn't so expensive ($79 is what I've found).

Thanks,

-Michael

[mcarland]

I've just hooked up an external monitor, and it seems to be working even when the built in LCD is not, so I don't think it is the motherboard problem covered by Apple.

When the monitor is on the fritz, I can see the faint image of what I had been looking at, so I'm pretty sure it is a backlight problem.

Here's where it gets weird. If I keep the base on a completely flat surface, and hold it perfectly still, no amount of wrangling the display will make the display return. But if I jostle the base, especially if I gently squeeze the hard drive area, the display returns. I have checked the backlight cable connection to the motherboard twice, and it seemed fine.

This doesn't sound like the backlight reed cable problem, does it? Any ideas on what to look for on the motherboard that could be loose and cause this problem?

Thanks,

-Michael

[Detrius]

Replacing the reed switch board assembly is a freaking pain. I look at this like replacing the top case kit in a TiBook or the neck on a G4 iMac. It's not fun AT ALL.

But it shouldn't be that expensive. We would sell it for $20 to $30. I don't recall the exact price off the top of my head, but it's about as cheap as parts get coming directly from Apple (there's shipping in there too, along with a markup to get to the price I quoted). Anyone selling it for $80 is ripping you off.

The other possibilities are the inverter and the actual backlight. The inverter is another dirt cheap part. The backlight is part of the LCD assembly. If you are going to bother to replace either the inverter or the cable, you might as well replace both, as it requires the same amount of work.

BTW, the cable plugs into the logic board right next to the memory/keyboard--it's not either of the ones that plug in near the hard drive.

I don't think it's the cable. Since the brightness is going up and down. If it were as simple as on and off, it would likely be the cable.

I hate to give you a specific diagnosis, as I don't have the machine in front of me, and therefore, I'm more likely to be wrong. But at this point, my vote is on the backlight itself.

[mcarland]

Thanks.

I opened it back up, and am certain it is the logic board now. I can move the display back and forth with no effect, but if I applied a slight twist to the front frame of the case, the display would go off and on. Keeping it on a flat surface, I could see that the back of the frame would not move at all. Pressure to the backlight cable, both at its connector on the mainboard and where it goes through the hinge had no effect. It seems to be most sensitive around the area under the hard drive, left of the processor.

So here's the sad part. I took it to the local Apple store to see if I could get it repaired under the logic board program, and of course placing it on the sacred counter healed all. Although the monitor would constantly go off and on for a week at home, it wouldn't even flicker in the store. Thinking it may be heat related, I left it there for an hour, but still nothing. One of the geniuses gave me a great idea, make a video of it doing it when it started again.

So I get home, set it up, and it's working perfectly, so I sit down and start reading a book. 2.5 hours later, the display starts going off and on, but it wasn't until the next day that it was bad enough again I could catch it on tape. When I go back in, I'll take the tape, and keep it running in the car with the auto adapter. I assume seeing it first hand would still be better than the video I made.

After googling, I found the backlight cable for $45 I think, which by you still sounds high, but I don't think I'll be needing one. Hopefully they will consider this part of the logic board replacement program, so I don't have to buy a replacement, which so far I've found for $230.

Thanks again,

-Michael

[STAT]

Michael,

What wound up happening? A friend of mine has a 500 MHz iBook and the backlight goes on and off (sometimes goes to half-brightness) when pressure is put on the left palm rest area (hard drive area). Did you ever figure out why this area seems to be where the loose connection is?

[Detrius]

If wiggling the logic board makes the difference, then this would seem to be related to the logic board repair extension program, even though this isn't a symptom listed.

[mcarland]

Originally posted by STAT:
Michael,

What wound up happening? A friend of mine has a 500 MHz iBook and the backlight goes on and off (sometimes goes to half-brightness) when pressure is put on the left palm rest area (hard drive area). Did you ever figure out why this area seems to be where the loose connection is?

I took it to the Apple store, and even though it had been driving me nuts consistently for a week, it wouldn't do it there. Even left it with them to run and warm up, in case it was a thermal problem, but no go.

Took it home, and of course it failed almost immediately. But the person had made a good suggestion. When it did it again, videotape it in action. That way, even if it won't do it in the store again, he can mark the repair form as his having seen the problem. Turned the video into a QT, but it displayed the problem at the store this time.

The logic board was replaced, under the repair program, and I haven't had a problem since. They even turned it around in record time. I dropped it off Sunday night, and it was back in the store on Wednesday afternoon. Can't beat that.

-Michael