Dated service document noting problem MacFixIt reader Peter Hilleard says he has found a document prepared by Apple's service officials in July 2001 indicating that there was prior knowledge of display cables being damaged in some iBook models. The document is located in the "Restricted: Apple Specialists" section of Apple's Knowledge Base, and is titled "iBook (Dual USB): No Display, or Dim Display, But Computer Appears to Operate Correctly."
Troubleshooting step 5 reads: "Verify backlight cable and LVDS cable connections are seated properly and that the cables are not damaged."
Hilleard writes "This indicates Apple knew as early as July 2001 that these display cables can be damaged - It is not caused by the user (because the cables are completely hidden inside the iBook.)
"This is therefore a design fault. Yet when asked, Apple has steadfastly denied that there are any known issues and have charged many hundreds of dollars to repair this fault for any iBooks outside of warranty. Nor has Apple warned users of their prior knowledge that the cables can fail or advise of any measures the user might take to limit the problem."
Loose screw Paul Bruneau notes a separate issue that may be affecting some users with iBook display problems, but seems isolated:
"About 6 months ago, the iBook started to instantly shut down to black with no warning. Within a couple days, it got to where I couldn't get it to start up. I disassembled the iBook about to the point where the motherboard is visible and tried it again--it worked.
"I reassembled it and tried again, and it failed to start up again. So I disassembled it a little at a time trying to see when it would start to work. Finally, through luck, I found the problem--a small screw had worked itself loose and was lying on the traces of the motherboard. I wonder if some of these other people's motherboard problems are the same cause. When I removed this screw, the iBook worked fine again."
UPDATE: There are several threads in the MacFixIt forums discussing the iBook display/logic board issue: