290 Tachometer Issues

[LJS30]

For quite some time my tachometer has not been functioning. So I installed a new cable and still it isn't working. How likely is it that the actual gauge itself has gone bad? Besides the gauge and the cable what would be next?

 

[used red MN]

Square up a proper sized nail with a hammer on steel
or grind it. Saw off the head and put it in your drill. Put
it in the tach and see if that will make it register. If it
does it is probably the drive gears. The drive can be
accessed at the link in the CAMSHAFT, TIMING GEARS AND HOUSING section, number 19. Take your nail and stick it in there and see if the drive spins free as if the drive teeth are stripped. Maybe can see if it even turns with the cable unhooked and the engine started, probably need a good flashlight for that.
AGCO MF 290 parts catalog

 

[LJS30]

Thanks for the assistance!! Well I hooked up the cable to a power drill on the drive gear side and guess what? The tachometer spins nicely. So it must be the drive gears. Is it a somewhat straight out swap?