Lubricate the vise assembly, the clamp on the left side of the saw, if it will not clamp onto a piece of wood. Rub some grease on the screw part of the assembly. This will allow the assembly to move up and down more freely.
Dismount a broken miter saw blade. Any bends or chips in the blade may cause shrapnel to launch into the air. Unscrew the the 4-mm nut located on left side of the blade's center with a 4-mm wrench. Safely remove the blade. Place a new one into position, and tighten the 4-mm screw back into place.
Replace a holder if you cannot properly fasten the wood to the miter saw because the holder is cracked. Using your hand, unscrew the wing nut on the side of the holder. Slide the holder out of the saw. Slide a new holder into position. Screw the wing nut into the hole about halfway down the holder.