Do all as Enzo said...
Also if you still have those mosfets you removed test them with a meter to make sure they were faulty, then at least it confirms that part. When changing out the output transistors due to output transistors failure it is a good idea to replace the driver transistors for the outputs. First time powering up an amp, with such a repair, it is good practice to use a light bulb limiter or current monitoring variac to make sure we don't fry the outputs or something else.
Also if you still have those mosfets you removed test them with a meter to make sure they were faulty, then at least it confirms that part. When changing out the output transistors due to output transistors failure it is a good idea to replace the driver transistors for the outputs. First time powering up an amp, with such a repair, it is good practice to use a light bulb limiter or current monitoring variac to make sure we don't fry the outputs or something else.