Original post by: dischercreative ,
Hi. The power ratings on the power adaptors are their maximum capacity. They do not jam 45 or 65 watts of power into the laptop they just have that capacity. For instance, if any of you are outboard boat owners you know that when you are puttering in to the harbor your 80hp motor is not running at 80 horsepower. It just has the "capacity" to produce 80 horsepower, but you have it throttled down. Now in the cast of power adaptors, if you were trying to run a 17" ibook off a 45watt power adaptor it likely will work but will be "flat out" trying to charge a larger battery and maybe supplying more power to the logic board. Running a 65 watt power adaptor on smaller iBooks just means you will always be running the adaptor "under" its maximum rated power output. Power is a product of voltage x current. These adaptors are likely rated for what they draw out the the wall outlet and not what they put "into" the computer. Power Jack issues can cause several problems, some include not seeing the battery, not charging the battery, and not being able to run the laptop at all. I also found breaks in the cables as well as non functional bi-color LED indicators in the "lighted" ring on the Apple OEM adaptors. The best solution I have for diagnosing the problems is to use or borrow someone else's known working iBook for comparison tests. You can easily narrow down a power adaptor cable problem when its symptoms move to another laptop along with it.