Two Tachs actually
Before the site went down I had posted I was having issues with a Tach dash where the Tach was pegged as soon as the key was turned
I finally got my hands on another Tach and upon trying that I found the Tach worked fine so the wiring was not at fault. That being said this second Tach didn't return easily to zero
I was shortly heading to the USA so brought both tachs and mailed to Phil Severance who has done some challenger gauges for me and also some previous Tach work
For those with an interest his repairs were as follows:
"The tachometer, that pegged, had an internal short that didn't show up until the tach was installed and grounded. I replaced the whole board and will sort the old board when I have more time. The tachometer that didn't zero had a lot of contamination in the meter. I replaced the board, balanced and calibrated the meter. Both should be good to go"
Thanks for the update.