I was really disappointed by the repeated failure of the power supply cord where it meets the RCA-like plug that plugs into my Apple Macintosh iBook computer... A problem that costs almost $100.00 to fix because you must replace the complete power supply adapter.
When you design a laptop computer you engineer all parts with the idea that your customer would use it as a laptop not a portable desktop. Apple has improved the power cord in its latest generation of laptops, however their are millions of 68000 based Apple Macintosh iBook and PowerBook that are working today whose power adapters may break.
I was replacing one broken iBook power adapter a year due to cord breakage. The iBook power adapter wire always failed in the same place at the molded plastic rubber-like strain relief. The molded perforated strain relief would crack placing all the strain on the wires which would soon break from constant flexing and pulling at the weak point. The weak point is the end of the cords plastic cover where the exposed thin lightly insulated wires that carried the power to the Apple Macintish iBook attach to the plug.
Apple engineers its computers to a much higher level then most computer manufacturers, however in this power adapter they missed the mark. This weakness was not resolved for 7 years until the release of the MacBook Intel powered laptops. Originally introduced in 1998 on the PowerBook PowerPC G3 style of Apple Macintosh laptops relatives of the original weak power connector were still being sold in 2006. Many small company's tried to address the power cord difficulty by offering third party power adapters but most went out of business. The original power adapters were wonderful in all respects except the delicate power cord to plug connection delivering electricity to the iBook laptop.
Strain relief on electrical cords has been a problem since the first cord was made. How many times have you seen someone pull on the electrical cord rather then grabbing the plug? During World War Two army's of the world had to engineer electrical devices that would withstand battle conditions and abuse by the young men that used them. This caused the most successful redesign of power cords and plugs for all electrical devices. All cords were redesigned with strong plastic covers and plugs were designed to grab the cover, insulated wires, strain relief and whatever else was inside so the connection was almost unbreakable. This same construction is still available in upgrade replacement plugs today.
Apple did not follow this rugged connector design philosophy. The cord to plug connection was joined only by a molded plastic strain relief. When the strain relief cracks the wires inside the plug between the Macintosh laptop power adapter cord and the power plug are exposed. At this point the wires accept all the strain and flexing from normal laptop use and soon fail.
The Apple Macintosh laptop power adapter plug to cord connection is not designed to be repaired. It is a custom plug and no replacement plugs are available to fix your power adapter so your iBook is on battery power until you buy a new Macintosh laptop iBook or Power Book power adapter. I attempted various fixes and found that none worked well until I used tape to secure the wire to the plug. My first repair using plastic tape worked perfectly for about a year then the tapes adhesive loosened and slipped off the plug. I decided that a better tape was needed so I used cloth surgical tape that conformed and adhered to the plug perfectly.
The tape, and the position of the wire are two parts to making this fix work. The third is securing the cord as soon as it breaks.Get some one inch cloth surgical tape from your local pharmacy for a few dollars. With the power adapter unplugged from the computer wrap the tape once around the plug starting just above the lighted ring to provide a strong adhesive connection between the tape and the plug. Leaving the tape attached to the plug carefully fold the power cord in a "U" so it passes the plug toward the computer socket and wrap several layers of tape around the plug securing the cord firmly to the plug. The plug can now be plugged in to your Apple Macintosh PowerBook or other laptop computer with the cord making a slight bend as it passes the edge of the computer.
This "fix" places all the strain on the replaceable tape and power adapter cord which was wonderfully engineered. The cord might look a little geeky if someone notices but your Apple Macintosh laptop computer works. You might have to replace the tape after a year or two but the power adapter will keep working almost forever.