Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

My trimmer , about a month old, has suddenly developed a "frozen" head.  The first day I had it, it was balky, right from the initial start-up.  I attributed this to a tangle or mis-alignment of the string, so I removed the spool, fiddled with the string, and it worked OK.  On 3 or 4 subsequent uses, same problem, and the same procedure usually got things right.  Yesterday, after a pause to refuel, she fired right up as usual, but the head refused to rotate.  I fiddled with the string, spool removed, wound, re-wound, etc., a half-dozen times to no avail.  When I removed the spool completely, fired  it up, I noticed that NOTHING was rotating!  Is the head connected to the engine via a cable running through the hollow shaft?  What would cause this problem?  I'm taking it to an authorized Stihl shop today, but I'm really curious about the cause of this, for I am exceedingly careful with my equipment....Thanks, guys..Phil