1970es 80es Acrotach Tach.

Any thoughts on getting @halifaxhops to test it?
I can test it, hook it to my 66 , just haven't done it, if I did test it and it all worked fine price goes back up, and if I test it and it smokes or something then it would have to be repaired I guess.. 35 is way to cheep for a great vintage tach, I better just mark it sold .