Just recently for some odd reason the ignition module on my HEI distributor went out after a fusable link burned into. When it did all of this the engine completely died and the needle on my Autoguage tach went from about 2500 rpm to 6800 rpm!

Well, I've since fixed the fusable link and replaced the module. So now the engine runs again but for some reason the tach still sits at 6800 rpm. So I tried a different tach on the same engine...it works. So then I tried the Autoguage tach on a different engine...still sits at 6800 rpms. The only thing it does do is when you apply power to the red and black wires the needle does jump a little bit back to 6700 rpms but once power is removed it goes back to 6800 rpms. Normally I would think the needle should return back to zero...but it doesn't. I've even taken apart the housing and I can't detect anything burnt or anything unordinary. Any ideas on what may have happened?

Send it back to Autometer for warranty.
Believe it or not they can probably repair it for less than a new unit.

Actually I'm not sure if they can fix this one or not....it's pretty old. I looked on the bottom of the mounting plate..looks like it says it was made in Feb 96. It's one of the $50 plastic 3 3/4 ones you can buy at Summit new. It's not a big deal...I got the tach from a buddy of mine but I found it wierd how it all the sudden doesn't work and yet I can't figure out why.