Originally Posted by
Rick Kirchner
I've seen this problem 3 different ways:
1) master switch is going bad and bouncing. Dash locks up.
2) internal power problem
3) using a line from the coil directly to the tach input (there are two, and one is supposed to take the trash that exists on a coil connection). This one will eventually kill the dash completely. If you don't have one, get the AIM tach amp. And then you need to protect that with a big-ass capacitor and a zener diode, because if the voltage drops below a certain point while cranking the amp blows. I lost two that way, and while the chip that needs to be replaced is only $1.89, the specialized equipment that's needed to replace such a small device will send you looking for a very expensive expert. Without protection, the amps are an $80 fuse.....