tach repo or rebuild ?

[yelmer]

hello i have a original tach that was not working and sent it in for a update i waited 4-1/2 weeks . so it came back sat . ok sunday i will install . well the tach did not work so i checked my wiring ok . now i must call the rebuild service and have them check it. i also i noticed the hand would stick at 2000 rpm when you blew on it . i almost bought one the the repo tachs has anybody never used one of these? are they any good ? I hate to do these process again with the old one send it in and wait.