I posted this from my phone the other day and deleted it somehow, so here it goes again.
Do to my lack of success searching for info on Tach repair I thought this may be of use to someone.

My tach needle was stuck at 1K with no response from any RPMs, four letter words or beating on the dash.

After you've removed the tach (sounds easy) from the dash start by pulling the black plastic shroud. Mark and pull the bulb mounts and signal wire. Disconnect and remove the wires and locknuts and plastic mount from the two wires with eyelets.
Next, remove the two little silver machine screws on the back (mind your tach needle on the other side).
At this point the dial and innards should be loose and may you may need to gently brake the old crusty cushion loose from the back by pressing on the brass screws from the backside.
The first problem is an old electrolytic capacitor, the one that looks like a little grey or black beer can. UPJ1H390MED Nichicon | Mouser
After about 25 years these usually dead or very near it.
A very simple 5 min. with a soldering iron and a $ .35 part fixed that.

Now to free up the needle I just gently put pressure on various parts of the tach dial while flipping the needle to find out what and where it was binding. It seems the brass supports under the dial face just needed a minor tweek. I just used a small screw driver and bent the braces very slightly and presto, a smooth needle. Be very careful not to bend the little coil springs inside.

Assemble and test tach an bulbs prior to shoving tach back into dash.
Happy revving.

 

Wow! Nice first post!

This is very useful info as the S30 tach's are prone to this kind of death. I have made a copy of this thread in our Gen Tech area:

https://www.zdriver.com/forums/240z-...-repair-40153/

 

Yes, thank you! Pretty sure this will be useful in the restoration of my 260Z.

 

I have a tach removed a few days ago from a 78 z with 02367 miles on the car. It went over a 100k so the tach has 102, 367 miles. Asking $170 shipped.