Pulled the dashboard instrument panel. Partially disassembled printed circuit sheet, rear cover and tachometer hardware. Then removed tachometer. Using a quick drying Electronic Cleaner and a lot of cotton tip swabs, I cleaned everything that looked like a contact or ground. After insuring everything was free of lint, reassembled all of the components. Reinstalled the dashboard Instrument panel. The good news; ”THE TACHOMETER IS FUNCTIONING PROPERLY”. The bad news; Don’t know what specifically restored the tachometer to an operating condition. In the future, if I ever have an electronic component that’s gets erratic, malfunctions or fails; my first step will be to thoroughly clean all of the associated contacts and ground(s). Thanks again to all who contributed. … larry Note: Having trouble posting a reply to the original thread.