Presto Reader: Coin Dispenser Jammed - Diagnostic Report... | terminalfaults.org

Technical Background:

The coin dispensing mechanism is typically controlled by a 24V DC solenoid. This solenoid actuates a mechanical gate or pusher to release coins. Jamming can occur due to foreign objects, coin debris, or solenoid failure. The control logic board sends a signal (likely a PWM signal) to the solenoid driver. The solenoid driver provides the required current to actuate the solenoid. A mechanical interlock or sensor may provide feedback to the logic board regarding the position of the gate/pusher.

Symptoms:

The coin dispensing mechanism is unresponsive. No change is dispensed upon valid card tap/transaction. Error message displayed (if any) indicates a mechanical fault or obstruction.

Possible Causes:

Foreign object lodged in the coin dispensing path (e.g., debris, gum, paper).
Coin debris or corrosion build-up causing mechanical obstruction.
Solenoid failure (open circuit, short circuit, or weak actuation).
Faulty solenoid driver circuit on the control board.
Mechanical wear or damage to the coin dispensing mechanism (e.g., bent gate, broken pusher).
Low voltage (under 23V DC) supplied to the solenoid, preventing proper actuation.

Solution:

1

Power down the Presto reader using proper Lockout/Tagout (LOTO) procedures: Disconnect the power supply at the breaker panel.
2

Visually inspect the coin dispensing area for any obvious obstructions. Use a flashlight to improve visibility.
3

Using a small, non-metallic tool (e.g., plastic probe), carefully attempt to dislodge any visible obstructions.
4

If the coin dispenser has an access panel, carefully open it (if permissible by the device security policy and only after LOTO).
5

Remove any coin debris or obstructions found within the access panel using a small brush or vacuum.
6

Restore power to the Presto reader following LOTO procedures.
7

Test the coin dispensing function with a low-value transaction. Observe if the mechanism operates correctly.

Safety Warning:

High voltage (120/240V AC) is present in the power supply circuit. Improper handling can result in electric shock. Always perform Lockout/Tagout (LOTO) procedures before servicing the device. Moving mechanical parts can cause pinch hazards. Wear appropriate personal protective equipment (PPE), such as gloves and eye protection.

Prevention:

Regularly inspect and clean the coin dispensing area to remove debris.,Implement a scheduled maintenance program to lubricate the coin dispensing mechanism (if applicable and manufacturer-approved).,Ensure proper coin management practices to minimize the introduction of foreign objects.,Periodically check the 24V DC power supply voltage to ensure it is within the specified range (23-25V DC).

Expert Tip:

Check the solenoid voltage with a multimeter while it is attempting to dispense coins. A significant voltage drop indicates a weak solenoid or a problem with the solenoid driver circuit. If the solenoid is getting correct voltage but not actuating, the solenoid is likely defective.

Frequently Asked Questions

•What type of coin validation system does the reader use?

The coin validation system is typically a combination of inductive sensors and optical sensors.

•What is the replacement procedure for the solenoid?

Solenoid replacement requires disconnecting power, removing the coin mechanism, disconnecting the solenoid wires, and installing the new solenoid. Proper Lockout/Tagout (LOTO) procedure is mandatory.

•How do I access the event logs for coin dispensing errors?

Accessing event logs requires connecting to the device using a diagnostic cable and specialized software provided by the manufacturer.

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What type of coin validation system does the reader use?

•What is the replacement procedure for the solenoid?

•How do I access the event logs for coin dispensing errors?

Related questions

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Solution:

Safety Warning:

Prevention:

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