my audiostrider600 it slipping when I peddal. What can be the problem?I've bought a new belt but I cannot figure out how to install it properly. in the manual, "how to adjust the belt" - it says , "insert the shaft of a screwdriver downward between the idler and the idler pulley". there is no place to gain leverage between the idler , which is flat, and the pulley. please advise.