Oil pressure guage malfunction

[btolman]

My oil pressure guage on my 83 spider started to work intermittently and then gave out. I suspected the bell shaped sending unit and replaced it with a new one. Unfortunately this did not solve the problem. So I now suspect the guage itself. How is the guage tested? Do I put a volt meter on the on the guage when the engine is running to check for electrical output from the sending unit?

Thank you,
Bruce