The gantry is one of the most important parts of a claw machine. So when it starts moving in one direction the moment a coin is inserted — before the player even touches the joystick — something's clearly wrong.
This is actually one of the most common claw machine issues operators run into. There are two likely causes: the joystick microswitch got damaged (usually from a player yanking the stick too hard), or the main control board has a fault. Here’s how to figure out which one it is.
Step 1: Check the Joystick Microswitches
Open up the joystick control panel. You’ll see four small microswitches inside — one for each direction: forward, back, left, and right. Each switch has two wires connected to it.
Here’s the trick: if the gantry is auto-moving forward after a coin is inserted, disconnect one of the wires from the “forward” microswitch, then power off, insert a coin, and test again.
- If the problem goes away — the microswitch is faulty. Just replace it with a new one.
- If the problem continues — move on to Step 2.
Replacement microswitches are available in our arcade spare parts collection.
Step 2: Check the Main Control Board
If the joystick checks out fine but the gantry is still moving on its own, the board might be the issue. Try these in order:
- Unplug the joystick cable from the board, then power on and see if the gantry still moves on its own. If it stops, the signal is coming from the joystick side — recheck the wiring. If it continues, the board is likely at fault.
- Enter the board’s test menu and test the forward/back/left/right motors individually. Refer to your machine’s parameter guide for how to access the test mode.
- Swap in a replacement board to confirm whether the original board is faulty. If the problem disappears with a new board, the original is defective.
Need a replacement main board? Browse our spare parts catalog or contact us with your machine model for compatibility advice.
Quick Diagnosis Summary
| Symptom | Likely Cause | Fix |
|---|---|---|
| Gantry moves on its own in one direction | Joystick microswitch stuck/shorted | Disconnect one wire from that direction’s switch to test; replace switch if confirmed |
| Problem persists after joystick disconnect | Main control board fault | Test via board test menu; replace board if confirmed |
Frequently Asked Questions
Why does my claw machine gantry move automatically after inserting a coin?
The most common cause is a damaged joystick microswitch — often from a player applying too much force. The second cause is a fault on the main control board. Follow the two-step diagnosis above to identify which component is at fault.
How do I know if the joystick microswitch is faulty?
Disconnect one wire from the microswitch corresponding to the direction the gantry is auto-moving. Power off, insert a coin, and test. If the automatic movement stops, the microswitch is shorted or damaged and needs to be replaced.
Can I fix this without replacing any parts?
Sometimes, if a wire is simply loose or making intermittent contact, reseating the connector can resolve the issue. But if the microswitch is physically damaged or the board has an internal fault, replacement is the only reliable fix.
Where can I get replacement microswitches or a main board?
Hiclawcrane stocks replacement spare parts including microswitches and main control boards. Browse our arcade spare parts collection or contact us for help identifying the right part for your machine.