Fujitsu F53 Bill Dispenser: Coil Failure Diagnostics -... | terminalfaults.org

Technical Background:

The F53 bill dispenser utilizes 24V DC solenoids to actuate the bill dispensing mechanism. These solenoids are controlled by a driver circuit, typically a MOSFET or similar switching device, which is susceptible to ESD (Electrostatic Discharge) and voltage spikes. Signal attenuation can occur due to aged connectors or damaged wiring. Ambient temperatures of -40C can affect the solenoid coil resistance and the viscosity of lubricants within the mechanism.

Symptoms:

Fujitsu F53 bill dispenser intermittently fails to dispense bills. The observed failure is reported as a coil failure within the dispensing mechanism.

Possible Causes:

Degradation of the solenoid coil insulation, leading to intermittent short circuits.
Failure of the solenoid driver circuit (MOSFET) due to ESD or voltage surges.
Mechanical obstruction within the dispensing mechanism, increasing the load on the solenoid and causing it to overheat.
Corrosion or loose connections in the wiring harness supplying power to the solenoid.
Low voltage supply: The 24V DC power supply is not providing the correct voltage, causing intermittent solenoid failures.
Extreme temperature affecting lubricant viscosity and mechanical movement.

Solution:

1

Visually inspect the wiring harness and connectors for any signs of damage, corrosion, or loose connections. Reseat all connectors.
2

Using a multimeter, measure the DC voltage at the solenoid connector when the dispensing mechanism is activated. Confirm a stable 24V DC supply.
3

Measure the resistance of the solenoid coil. Compare this value to the manufacturer's specifications (if available). A significantly different resistance indicates a faulty coil.
4

Check for mechanical obstructions within the bill dispensing path. Remove any debris or foreign objects.
5

Inspect the solenoid driver circuit for signs of damage (e.g., burnt components). If possible, test the driver circuit using a multimeter or oscilloscope.
6

Cycle power to the kiosk. A full power cycle clears transient errors.
7

Review the kiosk's event logs for related error codes. These logs can provide additional clues regarding the cause of the failure.

Safety Warning:

This equipment operates on 24V DC, which, while not lethal, can cause burns and shock. Always disconnect the power supply before performing any maintenance or troubleshooting. Lockout/Tagout (LOTO) procedures must be followed during maintenance to prevent accidental energization of the equipment.

Prevention:

Regularly clean the bill dispensing path to remove dust and debris. Inspect the wiring harness for signs of damage. Ensure proper cable strain relief to prevent connector damage. Consider using a surge protector on the kiosk's power supply to protect against voltage spikes. Schedule preventative maintenance checks every six months.

Expert Tip:

Use a thermal camera to check for hot spots on the solenoid driver circuit or the solenoid itself. Excessive heat indicates a failing component or a mechanical obstruction. Also, verify the 24V DC power supply's output under load; a failing capacitor can cause voltage droop only visible under load.

Frequently Asked Questions

•What is the typical lifespan of the solenoid in the F53 bill dispenser?

The lifespan varies depending on usage and environmental conditions. However, it is typically rated for several million cycles.

•Where can I find the manufacturer's specifications for the solenoid coil resistance?

Check the Fujitsu F53 service manual or contact Fujitsu technical support.

•What type of lubricant should be used on the bill dispensing mechanism?

Use a dry PTFE lubricant specifically designed for electromechanical devices. Avoid using oil-based lubricants, as they can attract dust and debris.

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the typical lifespan of the solenoid in the F53 bill dispenser?

•Where can I find the manufacturer's specifications for the solenoid coil resistance?

•What type of lubricant should be used on the bill dispensing mechanism?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: