Entry: iBook screen hinge design Monday, December 08, 2003



My everyday computer is a 2001 Apple iBook. It's pretty good, a bit slow by today's standards, but does most of what I need it to do very well. It started off life as a 500 MHz machine, but now it's running at 600 MHz, and the internal main bus is up from 66 MHz to a far more useful 100 MHz - in fact it now runs OS X painlessly. The overclock is not the subject of this article - I carried it out quite a while back and had not much of a problem with it - if you're interested, details can be dug up at http://www.xlr8yourmac.com.

One problem the iBook has always had since it was new is that the screen hinges creak terribly - in fact it sometimes feels as if the screen would break, it juddered and graunched so badly. Opening the screen requires a bold and decisive action to avoid this - adjusting it by a small amount was usually tricky, it was often easier to half close it then reopen it to the new position. Others have noticed the same thing - one of the overclock sites I came across also had a modification to the hinges to fix this issue - all it requires is that the friction rollpins are opened up a little bit. On its first take apart, I had a look at my iBook's hinges to see how it all went together. On that occasion I decided against the mod, since it requires quite a bit of dismantling, and I had enough to worry about with the overclock and hard disk upgrade. One thing I did notice though was how the iBook feeds the cables through to the hinged screen - it didn't look too well engineered, but well, I thought, Apple must have lots of experience of this, they know what they're doing and it seems to work, so I'm probably wrong.

9 months later my screen went black. At first I assume some horrible crash has taken place but on close inspection I see that the actual image is still there and working fine - it's the backlight that's gone. I tapped and jiggled a bit, hoping it was just a loose connection, but it wouldn't come back on. Then I closed the lid completely, opened it again and all is fine - until the screen is angled all the way back, at which point it cuts off again. A full closure and reopen will bring it back on. I soon discover there is a critical angle past which the backlight goes off. Easy fix - just don't open it any more than that... except that a week or so of using the machine and my back is aching like buggery, so something has to be done, and anyway there is no way I could accpet that sort of fault. In passing, I enquired of our local Apple repairers what the likely cost would be - a new screen is what they immediately suggested, and like the Canon G3 situation, is both the majority of the cost of a new laptop and total overkill for what must surely be a simple fault. That hinge design was also nagging at me....

I was reluctant to do a full take-apart on the main part of the machine at first - it's not particularly difficult but it's long winded, with about 50 or more tiny screws, and many little bits and bobs that need to be dealt with. Since the fault was in the screen, I decided to start with a that. I'd not opened the screen before, so had to feel my way, but it was quite straightforward (once I'd filed down the only very small hex driver bit I had anywhere near the right size so it fitted properly). In fact it was so straightforward that the main LCD panel nearly fell out - unexpectedly it's only held into its frame by four tiny screws. I quickly identified the inverter board that drives the backlight, and carefully wiggled the wires to see if there was a loose one somewhere. No luck - the fact that the backlight was affected by the screen opening angle was good evidence of a loose connection in the wiring, rather than a fault with the board itself. The fault remained, unaffected by my prodding and poking, so the fault didn't seem to be in this area. Next I turned my attention to the other end of the cable feeding the board. As luck would have it, this is one of the few connectors that can be accessed without taking the main machine apart - you can lift out the keyboard then the memory expansion cover underneath to get at the connector. I disconnected this, wiggled the wires, put it back... no luck, same problem. The cable runs from that connector through the hinge to the inverter board in the screen - disturbance at either end had no effect so the fault had to be in the middle of the cable - and right in the middle of the hinge. A full take-apart was now inevitable, and my concerns about the hinge engineering were seemingly well founded.

A careful 45 minutes or so later, the machine is in pieces. This time I have to dismantle the hinges altogether so I can get at the cable in its entirety. This involves unscrewing the hinges from the main chassis, and also, from within the screen shell, unscrewing two screws which hold the hinge cover in place. This is the metal-looking thing that you can actually see joining the screen to the main unit. Once done, the cable run is fully exposed. What happens is that a bunch of wires (about 5 or 6) is scrunched into a tight bundle, wrapped in a metallised cloth sleeve and tightly wrapped with cloth adhesive tape to form a cylindrical cable. This then passes in front of the hinge, turns a tight 90 bend to go through to the screen, and then spreads out again to link to the board. The bunched cable is trapped tightly between the hinge itself and various openings in the plastic shell and the hinge cover - it is more or less unable to move and in addition is strongly chafed by the opening in the main shell as the lid is operated. It is a recipe for failure. In addition, the fact that the bunch is unable to move means that over a short distance of this cable, say about 10mm, the full accommodation of the changing angle (about 120 total) must be met within this length of wiring. Again, this is certain to fail after a while - think about twisting a thin piece of wire backwards and forwards until it breaks. If a longer run had been allowed for accommodation of the angle, things would be better - but 30mm or so would be a minimum to guarantee reliability.

Sure enough on exposing the wires within this bunch, one was found to be broken clean in two. The others looked OK despite the strain they must be under. I quickly fixed the break and bound up the cable again. I looked for ways to alleviate the twisting problem, but there is so little room - a little bit extra could have been allowed for in the hinge design, but it wasn't, so things are very very tight. Still, it looks nice, so that's OK then.... From now on I'll be moving the screen far less than I used to. Reassambled, everything is now fine (and I finally fixed the creaky hinges) - but I wonder how long it will keep on working. More worrying is that through the other hinge, there is a similarly tightly wound film ribbon cable carrying the image data to the screen. This cable is extremely fine, and if it broke, would be just about impossible to fix. No doubt a replacement isn't listed as a service part. So, in conclusion, while I'm a great admirer of the industrial design of Jonathan Ive, who designed the iBook, I feel that some better engineering in the hinge area would benefit the machine greatly. It would only take a few extra millimetres of room within the hinge itself, and some attention to where the cable goes as it passes along the front of the hinge - the key factor is that the cable should not be trapped tightly here, but allowed to move freely to accommodate the range of screen angles over a reasonable length of the cable.

   9 comments

Bat
December 30, 2008   08:59 AM PST
 
Seem to be having the same problem with a 3 year old G4 iBook. It's been going on for several months. I got a replacement inverter cable, but the prospect of taking the thing apart is daunting. Thing is, I take this machine on the road with me and if that cabling really conks, I'm up you-know-what crick.

Part of what's holding me back is what if I take this thing apart, replace the cable, and put it back together and that doesn't fix it. But, based on everything I've read, I'm pretty sure it's the inverter cable thing. Anything else, I think there'd be other symptoms. We have a couple of shops here in the area I could take it to, but they all want you to leave it for a couple of days and I'm disinclined to do that. I host, manage, and update a number of websites for different clients and all that client info on here, logins, passwords, and credit card info would all have to be wiped off the drive and then re-installed for one thing. This seems like a lot for something that somebody actually experienced in working on these things could probably fix in no more than a couple of hours at most.
Geert Dekkers
January 26, 2006   05:55 AM PST
 
Hey all,

I fixed my iBook having the same problem a while ago using just some telephone cable. Just connected them (or soldered -- it was a while ago).

And had ample room to stick the repaired cables to the display back panel.

Only -- a year or so later, and the problem is coming back...:((
Neil
February 16, 2005   01:35 PM PST
 
Check out pbparts.com - they sell replacement inverters, inverter cables, and video cables.
Dana Coe
January 13, 2005   08:36 PM PST
 
So does anyone have pointers on where to pick up a replacement cable? I ordered a new screen, and now I'm annoyed that it didn't come with a new cable.
Ryan at mirum dot org
November 4, 2004   03:26 AM PST
 
This all sounds way too familiar. I fixed my backlight cable a month ago, and now it's failing again. Anyone have a line on a replacement cable? Apple won't sell me one, and neither will any service depot I've found.
Marian
October 11, 2004   07:30 PM PDT
 
I have the some problem with my iBook G3 12", right now the machine is disassembled on my table. There is the inverter cable betwen the matherboard and the display broken. I bought a new one (the cable) but have no courage to disassemble the display itself. Does anybody now how to to it? The four screws on the sides are removed, but the white cover and the display panel stick together either. Maybe glued?
Thanks for any good suggestion.
Marian
Mel
September 7, 2004   08:41 PM PDT
 
It's not just Mac's that have this problem. I have an AmiloA that has decided it will blackout on me if I try to adjust the angle of the screen.
I have to tilt mine back because forward movements seem to trigger off the black screen, and I have to shut down to get the image back. I would love to try to repair it myself. I have steady hands but unfortunately no laptop repair experience! Any advice?
Jon
July 21, 2004   03:11 AM PDT
 
I had the exact same problem with my iBook. Took it to the repairshop but they wanted to replace the entire screen for an insane amount of money.. Knowing that it probably was just a broken wire I took it back without getting it fixed.. I opened it up and it turned out that I had two completely broken wires..

I ended up with just buying a replacement cable instead of trying to fix it myself (too much hassle).

At least the new iBook's have a new design regarding the screen - that's good because the old design truly sucks reliability wise.
Mike
March 17, 2004   02:45 AM PST
 
I, like you, have used Macs for ages, and by publishing business runs on an iBook. Running 9.1, just as when delivered (it was one of the first white ones).

The screen has the same problem, exept mine only works when it's pushed right back. I thought it needed cleaning, and had a can of carburetter clean handy... I run some off a plastic spoon into the hinge, only to discover the spoon is dissolving a bit! The screen fails to operate at all. So I try some WD40. The screen now works as well as it did before the chemistry lesson.

I want this computer to last many more years, and have neither patience, courage or steady hands sto do the job.

Before I started I called the Apple Centre in Cardiff (02920 620839) The expert there told me the problem was with a logic board, and the machine needed to be sent back to Appple for repair. I don't think he could listen to the problem, let alone come up with a solution. They want my money, not my loyaltMike

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