I've never heard of it before reading your link but if you insert a penny or washer behind the tensioner and in the 9 o clock position it will stop the squealin in many cases.
Does the terminal go onto the 'W' on the alternator, that's how I wired a Tachometer to my 200tdi Defender, if so, as above sounds like a knackered alternator
Went and picked second hand alternator mate gave me a lift he dropped me at work and rang me bout an hour later saying he'd fitted the alternator and it's working fine. I didnt even ask him to do it, he said he was bored and just did it lol