Your 7.5A ignition fuse keeps blowing in my 1990 Toyota celica?

You have a short to ground or a bad connection that is causing the circuit to "draw" too many amps, causing the fuse to go out. This will be hard to diagnose. Sometimes the wires in the distributer module area inside the distributer cover will crack with age and allow the spark out to ground. Could be a bad module or igniter module on firewall.

Do you have an aftermarket alarm? did they chop into your ignition circuit to add an engine kill? That is often a cause. check your battery clamps first. If there is a crustiness, that will cause a current problem. Always check your battery before all else. 9 out of 10 it originates there. Good luck. sounds like mechanic time...