If you can make one, I would buy one from you.
What steps do I need to take to make this happen?

My tach is in the #2 catagory - jumps to life now and again, but is all over the place. I would rather get a known working item than a used tach amp that might work for a while and quit.

I remember seeing these for sale on Ebay last year, but was skeptical. Then I found this thread, but was too late.

Please let me know if a purchase is possible.

Thanks