I'm planning to replace the cable on my now backup 60watt charger for my 13" MacBook Pro and have a question. I've cut the old cable at the strain relief and cracked the charger case, the two wires connecting that cable to the board are covered with shrink tubing which appears to cover perhaps a small device. None of the replacement cables I've seen show anything but plain wires at the charger end. Is this significant? It almost looks like it conceals a push-on connector. Also any advice from people who've tried this would be appreciated, including but not limited to what to look for in a replacement cable. Thanks.