Tach electrical help?

["Lonn Howard" <hoops@owt.com>]

Just put the tach back in the dash yesterday and now when I turn the
ignition to the run position it is pegged at 7000 RPM with the car not
running.  I'm afraid to start it.  The connections are keyed so you
can't hook it up wrong, and I haven't messed with the coil.  Any ideas
what is happening?  Is my tach toast?
Lonn Howard
'70 TR6  -mine
'71 TR6  -in my garage
'70 MGB GT  -ours
'89 Saab Turbo Convertible  -hers

"We are but temporary custodians with an obligation of preservation."