all faulty fuse clips were replaced on the boards that were sent to me.
As Marty said this is a necessity. after the clips are replaced then you can check for further problems.

 in some instances faulty fuses can cause problems also, especially when there has been faulty fuse clips replaced (fuses can run hot due to the bad connection to the fuse clip and damage the connection between the fuse ends and fuse wire inside the fuse) so if you are unsure replace the fuses.

After you have sorted the electrical side of things you will want to make sure that the flipper coils are held tight in place, you don't want your coils moving around.
also check that there is minimal moment in the flipper linkage between the pawl and shaft ( you will lose power / energy through excessive wear on any linkage / plunger on any solenoid in your machines)

also check that the flipper is not dragging on the playfield due to excessive wear in the flipper bush or the flipper is not to tight in the bush. (it should have some movement when you pull on the flipper)

make sure all the connections in the wiring to the flipper board is fine