1971 GS Stage 1 Tachometer

Hi all, the tachometer in my recently-bought GS doesn’t work. Where can I find online resources such as a wiring diagram, or a system description, that will allow me to troubleshoot it?

Cheers

 

If it's OEM, more than likely it's the circuit board. I repair these BTW

 

I just sent five (yes, 5) tach's to Scott Moody for evaluation and repair. took one (1) week and I already have 2 back...

 

Scott- lol. You beat me to it.

 

So what’s the setup, a sensor generating pulses from the teeth on the ring gear, feeding a PCB in or near the gauge? I am in Australia and I don’t want to send the PCB to the US if I can avoid it.

 

Scott repaired two for me. Both work flawlessly.

 

Thanks for the information, that gives me a starting point. Cheers

 

No one should have 5 tachs. That's just wrong lol.

5 at one time, from one person, is a record by the way.

 

As Larry said. You will need a signal generator, square wave with variable duty cycle, 30 to 400 Hz, 0 to 12v, and a frequency standard.

I've heard of people using a battery charger, as it generates 12v, "dirty" DC with a 60 or 120 Hz A.C. component but iv e never tried it.

60 Hz = 900 rpm
120 Hz = 1800 rpm

 

I only started with 1…. Then an original one, the a repro, then the hood tach (in which you said was odd- as it was a mix of original and repro??), then another original…. Lol.