Digital Gauge suddenly stopped showing RPM'S
 

fixed

Two causes, one, no tach pulses coming from the distributor. Two, defective part on the cluster circuit board. Tach pulses originate from the spark module in the distributor. If the cluster is the cause, then you need to send your cluster to a repair station.
Why don't you post what year C4 you have? No one here is clairvoyant and they aren't all made exactly the same.

I've owned four Corvettes, one at a time, and driven every day since 1966 and I cannot tell what year Corvette that is in your picture. Also, there is no guarantee that the Corvette you are asking help for is the same year as the picture. I and others spend their own time and energy trying to help those asking for help on this forum and posters really shouldn't expect us to open their public profile, identify what year from a 1 inch square picture, stir tea leaves, or any other method than the OP making two simple keystrokes. Contrary to your belief, everyone else in the world does not sit up late at night thinking about your Corvette.

Amend JFB... about time.... its been said again for all the newbees out there, and some that should know better

Getting back to your problem-- If your car is equipped with a tach filter, I would check it out. It is a common problem and easier to get to than removing your cluster.

I think it's hilarious when washed up old people try to be kings of online forums. Shouldn't you be out gardening or getting a sponge bath, and not sitting online condescendingly talking to other Corvette owners who purchased theirs first Vette at least 30 years after you?

Wouldn't a simple reply of "Sorry, it's an 84" have been a little better? To attempt to belittle someone who appeared to me was trying to help you is not the way to win friends or get someone to answer your questions now or in the future. You are probably a very good guy with good intentions. Try stepping back and tempering your responses and you will find that not only here but in other areas of your life things will go much smoother.

If I could lend some concrete advice for your problem I would. I think the tach filter is a good place to start however. Take care.

90Indy