1994 Ford probe 2.0 DOHC ?

Some how the harmonic balancer is wobbling. He replaced the V belt that goes around the alternator, water pump and of curse the crankshaft, he replace the belt 3 months ago, again 2 weeks ago and once again last week. The belt shreds when it breaks. My friend has a Haynes manual but really don't say anything about the pulley. I find it real odd the harmonic balancer has to be replaced, since that's a part that doesn't break or go bad. But it does need replacing, I've looked at it and sure enough it does have a wobble to it. We both tried searching all corners of the internet came up empty. Thank you for your help!!!