I bought this tach at the Quick Times swap on Saturday, The seller was impoverished in terms of info: " I don't know" (a) if it works (b) what it came out of (c) how much is the price? It was on a shelf in his garage for over 30 yrs. (probably longer) If any one here can provide info it would be great, The ign, & grnd, are marked as well as the CAL POT marking and Inspected by #312 Obscured o ther numbers appear to be 99???10. The case is light blue plastic, no 4-6-8 switch, and while the face appears blue , it's the lights in my shop. Does any place repair them?