Tach replacement

[Rivetboy]

My 0 to 4000 rpm tach with an optical pick up has failed. It is a 12 volt model out of a 91 tc2000
cummins. 5.9
The optical sensor is fine the tach after bouncing for a few hours stuck at 1000 rpm
Any suggestions?
Have a couple of pictures will post when I get home
Thanks

[Rivetboy]

here we go

[Tango]

Check out "Tiny Tach" for diesels.

[Rivetboy]

Thanks Tango, cool little item but being an old aircraft instrument repairman I gotta go analog.

[Tango]

I would much rather stay all analog myself but installation on the tiny tach unit is so much simpler I decided to be lazy on that one.