> For the complete documentation index, see [llms.txt](https://docs.verifone.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.verifone.com/hardware-products/hardware/petroleum-devices/c18-r2/c18-r2-installation-guide/troubleshooting-guidelines.md).

# Troubleshooting Guidelines

## Power Supply Unit

Terminal fails to power on even when connected to a confirmed functional wall outlet.

{% stepper %}
{% step %}

#### Unplug the PSU

Unplug the PSU from the wall mains socket.
{% endstep %}

{% step %}

#### Disconnect the terminal

Disconnect the 24V DC barrel connector from the rear power port of C18 R2.
{% endstep %}
{% endstepper %}

{% hint style="info" %}
**NOTE**: Connect the DC barrel plug to the terminal first, then plug the AC mains cord into the wall outlet when reinstalling a new PSU.
{% endhint %}

## System Reset Instructions

The C18 R2 terminal is designed for continuous mains power operation post-installation. Follow this procedure for forced reboot:

{% stepper %}
{% step %}

#### Disconnect power

Unplug the power supply adapter from the wall socket.
{% endstep %}

{% step %}

#### Trigger controlled power-off

Flip open the side interface cover, insert a pin into the **RESET** button and hold for 5 seconds to trigger controlled power-off.
{% endstep %}

{% step %}

#### Confirm shutdown and restore power

Confirm all LED indicators on the terminal are fully extinguished, then reconnect the PSU to mains power.
{% endstep %}

{% step %}

#### Allow the terminal to boot

The automatic boot sequence will initiate upon power restoration.
{% endstep %}
{% endstepper %}

## C18 R2 Fails to Power On

{% stepper %}
{% step %}

#### Verify mains voltage

Verify the wall power outlet supplies stable mains voltage.
{% endstep %}

{% step %}

#### Test the PSU

Test with a spare compatible PSU adapter.
{% endstep %}

{% step %}

#### Replace the mainboard

If the issue persists after PSU replacement, replace the mainboard assembly.
{% endstep %}
{% endstepper %}


---

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