inside the housing behind the tach there is a little disc like thing that the wires from the tach plug into there are also diode like things on the disc . any one know what this is called and where i can get a new one . mine is a little burnt looking . i also need a picture or info on where the wires plug into. thanks guys i hope you can help

Congratulations! You just found the Tachometer Circuit Board. Now if you can just find a replacement. lol.
I haven't had to replace one of those in a long time so I doubt they are still available from GM. Try some of the Gauge Restoration web listings in the Hemming's site. If they can't fix it they may know where you can get a new one.
I remember hearing or reading something about someone repairing their 68 tach with repo parts for a 69 - but I don't remember where or when that was.

ok so i need a tach circuit board. where can i get one? i called a couple of tach people in hemmings and they want to redo the tach for at least $150 . i dont want to put that much money into it. anyone have any ideas to get this thing to work

The little board wasn't cheap when I was getting them from GM. Try some of your local Speedo Repair shops - they may have a source or even someone who could fix them in the area.