I have a 80 z28 and the factory tach is stuck at around 4500RPM.  When I start the car you can sort of see the needle move a little but other than that nothing happens.  I hate the Auto Meter tach I have and would really like to get the factory one working again. Is this a common problem? possibly printed board that's screwed? or am I better off just buying new gauges?

Thanks for the help.