I picked up a "Peerless Instruments Co." tachometer (5,000 rpm) for $1.00 at my local recycle store. There are four green wires coming out the back. Is there a safe way to sort these out without frying it? I can take it apart and investigate more, but just don't want to destroy it. Are tach's generally wired downstream of the 12 to 6 volt resister? Any help would be appreciated. Thanks. :confused: