Stewart warner Green line Tach. Repair

[GreenLS6]

Welp I have A NOS Stewart Warner Green line Tach and gauges. I Hooked up the tach like the Papers say , I double checked and even googled it.. nothin happins...Grrr Hoping it's not fried. I have had older Sun tachs that needed a tach adapter box. And found different answers on this tach. Well it's time to ask you guys. Or is there anyone who repairs these tachs as a stand alone unit??