mallory 11k tach hook up problems help please !

Did you buy it new? Either the tach is bad or it was a rare special order for positive ground, or the green wire is "pinched" and grounded somewhere

The mallory tach is used... malllory says "they do NOT make tachs anymore" .

I'll pull the cover off and look inside for a pinched green wire ..
do not think it is a pos. ground unit.. !