[Alpines] Messed up Series V tach

[awtiger at cox.net]

(Sorry to bomb the Tiger list with this, but I figured that since Tigers have roughly the same tach setup as Alpines, I'd bounce this off of you guys, too...)

I'm wiring up a Series V tach in my race car (Alpine) that I got from a friend of mine. The tach looks to be in excellent condition but my friend had said that he had never had it in his car and that it was just a spare. Therefore, he didn't know if it worked or not. 

Well, I've got it wired up just like the book says, complete with a good ground, and all I get out of it is very erratic, jumpy movement and a general tendency to lag behind the motor when I rev it up. Once it's revved up, it reads way too high (when it's not bouncing all over the place). I searched the SAOCA forum and found a tach thread from January that appeared to be about the same situation as I'm having. Just as that fellow did, I cleaned the metal bracket that goes around the loop and made sure it was getting good contact with the contacts in the tach. Unfortunately, my problem still persists. The only difference between this other fellow and me is that I don't have the luxury of knowing if this tach worked prior to me installing it. 

Any thoughts on this? Should I just send it off to Nysonger or some other instrument place to be rebuilt? Is there something else I should look at? Any help would be appreciated.

Thanks much,
Andy Walker
Edmond, OK
B382001600LRXFE
B9006857LRX