Tacho not working

[supercow55]

g'day,
when i bought my TC gem there was an Autometer Tacho mounted where the clock is normally situated in the instrument panel. The tacho worked perfectly but when i put in my CD Tuner it started playing up. I found that a wire had come lose and so resoldered it. A week ago the tacho just stopped and now won't work at all. I've checked all my connections and resoldered them, checked to see if theres current flowing through them. But the tacho needle is stuck on 1500rpm and just won't move. I don't think the tacho itself is stuffed so if anyone knows anything else i should check to find the problem that would be very much appreciated. Sorry bout the long post, Cheers Ben

[pazzo_gem]

sounds like a toasted tacho to me. the wires on the tacho are white, green, black and red. white is lights, green is negative to the coil, black is earth and red is ignition power. pull the tacho out and wire it up to another car to make sure it works. if it does follow the wiring in the car and make sure it isnt shorting on metal somewhere, make sure the power (red) fuse is good, make sure the terminal on the coil (green wire) is a good crimp and clean. make sure earth is to a clean source (sand the paint away where the earth connects with the body).
if your still fucked go see an auto elec.