Dejavoo Z11 Freezing Troubleshooting: Technical... | terminalfaults.org

Technical Background:

EMV/NFC transactions involve secure cryptographic processing. Large transactions may trigger buffer overflows in firmware, exhausting RAM. Power supply fluctuations (voltage dips) can cause processor instability, particularly if the internal capacitor ESR (Equivalent Series Resistance) is high due to aging. Increased computational load during complex transactions can expose pre-existing hardware faults like marginal memory chips. High ambient RF/EMI can also induce unpredictable behavior.

Symptoms:

Dejavoo Z11 terminal freezes after processing a transaction involving a higher than normal data throughput or a larger monetary value. The touchscreen becomes unresponsive, requiring a reboot.

Possible Causes:

Software bug: Firmware handling of complex or high-value transactions contains an unhandled exception leading to a crash.
Insufficient RAM: The transaction data exceeds the available RAM, causing the terminal to freeze.
Power supply issue: Voltage drops below the minimum required level during peak processing, leading to processor malfunction.
ESD event: Static discharge during card insertion or touchscreen interaction corrupts data or damages components.
EMC Interference: External Electromagnetic Interference is causing the device to malfunction.
Faulty capacitor: Aged capacitors in the power supply or on the mainboard exhibit increased ESR, reducing their ability to filter noise and provide stable voltage.

Solution:

1

Safe Handling: Unplug the Z11 from the power outlet.
2

Inspect the power adapter: Ensure the power adapter is the correct voltage (typically 9V or 12V) and amperage. Check for damage to the cable or connector.
3

Test the power outlet: Verify the power outlet provides stable voltage using a multimeter.
4

Reconnect power: Plug the Z11 back into the power outlet.
5

Reboot the terminal: If the terminal is still frozen, perform a hard reset (consult the Dejavoo Z11 manual for the procedure – typically holding down the power button).
6

Process a smaller test transaction: Attempt a transaction with a small amount to see if the issue is related to transaction size.
7

Check for software updates: Connect the terminal to the network and check for available software updates. Install any updates to address potential software bugs.
8

Factory Reset (If Permitted): Consult Dejavoo support FIRST to check if a factory reset is allowed under PCI-PTS rules without voiding warranty or triggering anti-tamper mechanisms. If permitted, perform a factory reset.

Safety Warning:

Electrostatic discharge (ESD) is a risk, especially in dry environments. Use anti-static precautions when handling the terminal. Do not attempt to open the terminal casing, as this will void the warranty and potentially trigger anti-tamper mechanisms. Ensure the power cord is not a tripping hazard. Ensure the terminal is placed on a stable, dry surface. Do not use the device near water or excessive moisture.

Prevention:

Regularly clean the touchscreen with an anti-static wipe. Ensure the power cable is not strained or pinched. Avoid placing the terminal near sources of electromagnetic interference (e.g., microwave ovens, motors). Schedule regular reboots of the terminal to clear temporary files and refresh memory. Consider a UPS (Uninterruptible Power Supply) for stable power.

Expert Tip:

Before performing a hard reset, try a 'soft reboot' (if the device is responsive enough to navigate menus). Soft reboots often clear temporary software glitches without data loss. If freezing occurs only with specific cards, inspect those cards for damage (e.g., bent EMV chip). A failing or dirty chip can increase processing time and potentially trigger buffer overflows.

Frequently Asked Questions

•What is the recommended cleaning procedure for the Z11 touchscreen?

Use a lint-free cloth dampened with isopropyl alcohol. Avoid harsh chemicals or abrasive cleaners.

•How do I check the firmware version on the Z11?

Navigate to the 'Settings' menu, then 'About' or 'System Information'. The firmware version will be listed there.

•What are the power supply specifications for the Z11?

Typically 9V or 12V DC, check the label on the original power adapter for the exact voltage and amperage requirements.

Dejavoo Z11 Freezing Troubleshooting: Technical Diagnostic Report

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the recommended cleaning procedure for the Z11 touchscreen?

•How do I check the firmware version on the Z11?

•What are the power supply specifications for the Z11?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: