First here is the info on the car-- '68 SS396 Camaro with the in dash Tic-Toc-Tach. After doing a frame off restoration , including new wiring harness under hood, my tach now works. The problem is that it does not give correct reading. It seems to be approximately twice what it should read. In process of the restoration I did get rid of the original points and went to an electronic system using the original distributor. I have had the car since '79 and used it as a daily driver for many years. Back then the tach never worked and I was pleased to see it actually did work. I am hoping that some of you car nuts might be able to give me an idea or 2 on what might be wrong. Thank you in advance for your input.

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tachman here:
there are no filters for this tach. the problem is in the white electronic circuit board, most likely a defective transistor. i have been repairing these tachs for 30 years and can repair yours.
www.tachman.com:thumbsup: (http://www.tachman.com:thumbsup:)