These are the possible reasons and solutions

Check the CW (claw) fuse on the gantry fuse board - replace with 3A fuse (not 10A)

Open claw case and check to see if solenoid is burnt out

Check the wires at the point they enter the solenoid, are they broken?

Check the connections to the left right unit. The plastic connector box in the left right unit where you screw two small screws in.

Check the wiring loom for a possible break in the wire to the claw. Slide the gantry backwards and forwards and left and right - as the caterpillar clips do the U bend, inspect in between for a break - if you can physically spot a broken or partially broken wire you will need to solder an extra length (5 cm max) of wire and use heat shrink - or order a new wiring loom

If you can't see a break you can test each wire for continuity one by one using a multitester. If one of the wires has no continuity and you can't see where the break is, order a new loom.

Check to see if the voltage goes up on the needle - that indicates everything is OK with the PCB board - the problem is usually then up in the claw/gantry area

If the voltage needle doesn't go up when the claw is supposed to close, try replacing the PCB board

Potentiometers may be faulty change

The 48V line on power supply may be gone. Change power supply

If claw closes on red button but not with coins, it is on a recurring hard grab and has a faulty hard grab relay on board- on some boards this is removable and we can send a replacement. When you push the red button it only does the voltages you have set up and uses one of the normal relays.