---
title: "The buttons on my V400m card terminal aren’t working"
slug: "the-buttons-on-my-v400m-card-terminal-aren-t-working"
updated: 2026-06-16T13:00:48Z
published: 2026-06-16T18:16:39Z
canonical: "mysupport.roller.software/the-buttons-on-my-v400m-card-terminal-aren-t-working"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://mysupport.roller.software/llms.txt
> Use this file to discover all available pages before exploring further.

# The buttons on my V400m card terminal aren’t working

## Problem

If your V400m card terminal appears unresponsive, it might be due to a faulty keypad. Common causes for a faulty keypad include:

- The terminal was dropped or physically damaged.
- Dust, sand or debris is lodged under the keys.
- Water damage to the device.
- General wear and tear.

A faulty keypad makes it harder to take guest payments or access admin functions which can cause unnecessary delays at check-in or point of sale.

## Solution

If you’re having difficulties with the keypad, carefully clean the terminal while checking for signs of damage. Then run a diagnostic to confirm if the keypad is still working or if the terminal needs to be [replaced](/v1/docs/choose-and-order-roller-payments-terminals).

## Guidelines for cleaning your card terminal

Follow the guidelines below when cleaning a terminal to make sure you don't accidentally trigger the TAMPER alert. Triggering the TAMPER alert on the device makes it unable to be used.

- Don't vigorously scrub or shake the terminal.
- Don’t pour or spray any liquid, sanitizer, or disinfectant directly onto the terminal.
- Don’t use bleach, hydrogen peroxide, thinner, trichloroethylene, or ketone-based solvents. These substances can cause rubber and plastic to deteriorate.
- Don't vigorously rub the terminal with a dry towel or cloth. This can cause an electrostatic discharge and damage the device.
- Don't clean the smart card reader, this voids the warranty.
- Avoid touching the battery contact points.

## How to clean your card terminal

1. Power off the card terminal.
2. Disconnect the power cable from the terminal.
3. Slightly dampen a clean cloth with water.
4. Put a few drops of a cleaning solution on the dampened cloth. Don’t apply cleaner directly to the terminal.
5. Gently wipe the damp cloth over the keyboard and display.
6. Wipe the terminal with a clean dry cloth.
7. When the terminal is completely dry, reconnect it to the power cable and turn it on.

## Run diagnostics on the keypad

After cleaning the terminal and confirming there’s no external damage, run a diagnostic on the keypad to confirm if each key is working correctly:

1. Press **9 + Green** to open the **Settings** menu.
2. Scroll down and select **Diagnostics**.
3. Select **Keypad.**
4. Select the **blue arrow** button to start the test.
5. Press each individual key on the keypad.

> [!WARNING]
> If one of the keys is unresponsive, you will likely need to [order a replacement terminal](/v1/docs/choose-and-order-roller-payments-terminals).

## Learn more

- [ROLLER Payments card terminal troubleshooting](/v1/docs/troubleshoot-roller-payments-card-terminals)
- [Why does my ROLLER Payments terminal show a TAMPER error?](/v1/docs/why-does-my-roller-payments-card-terminal-show-a-tamper-error)

## Related

- [Set up Zebra ZD410 for sticker printing](/set-up-zebra-zd410-for-sticker-printing.md)
- [Why can't I take payments directly on a wireless terminal?](/why-can-t-i-take-payments-directly-on-a-wireless-terminal.md)
- [The buttons on my P400 Plus card terminal aren’t working](/the-buttons-on-my-p400-plus-card-terminal-aren-t-working.md)
- [Choose and order ROLLER Payments terminals](/choose-and-order-roller-payments-terminals.md)