Zebra MC3400 troubleshooting: charging, scanning, keypad, Wi-Fi

CauseThe battery is empty, not seated, or the cradle or cable is not getting power. The charge LED stays off when the device is not seated correctly or the charger has no power.

Fix

1. Take the battery out and refit it. Press it down until both battery release buttons spring back.
2. Check the cradle's power supply and cables, or the USB power adapter. Try another outlet.
3. Seat the MC3400 firmly in the cradle. The charge LED should turn solid amber.
4. Give an empty battery some charging time, then press and hold Power until the Zebra splash screen appears.
5. If it still does not start, try a charged spare battery.

CauseFast blinking red (two blinks per second) means a charging error: the temperature is too low or too high, or charging took too long (typically 8 hours). Solid red means the battery has reached the end of its useful life.

Fix

1. Move the device and cradle to room temperature. Zebra's troubleshooting table says the battery does not charge below 0 °C or above 40 °C, which can happen after work in a cold store or in direct sun.
2. Take the device out of the cradle, wait a few seconds and put it back in to restart charging.
3. If the battery connectors look dirty, clean them as described in the maintenance chapter of Zebra's Product Reference Guide.
4. If the LED is solid red, replace the battery. Use an MC34 battery (BTRY-MC3X-70MA-01 or BTRY-MC3X-7BLE-01) to keep the IP65/IP67 sealing.

CauseThis is normal. When you take the battery out, the MC3400 turns off the display and goes into a low-power state. It holds the Wi-Fi connection for 30 seconds (the LED blinks amber) and keeps what is in memory for up to five minutes.

Fix

1. Optional: put the device in Battery Swap mode in the Battery Manager app first.
2. Push in the two battery release buttons and remove the battery.
3. Fit a charged battery within 30 seconds to keep the Wi-Fi session, and within five minutes to keep your open apps and data.
4. The device resumes on its own. If the swap takes longer than five minutes, unsaved work in open apps can be lost.

CauseDataWedge is off or not set up for your app, the cursor is not in a text field, the barcode type is disabled, or the barcode is damaged or out of range.

Fix

1. Touch the text field in your app so the cursor blinks, then pull the trigger or press a scan key and hold it.
2. Test with Zebra's DWDemo app. If DWDemo scans but your app does not, the problem is the DataWedge profile for your app.
3. Check that DataWedge is enabled and that the barcode type is enabled in the profile. Our DataWedge setup guide shows how.
4. If only the crosshair appears and nothing decodes, Picklist mode may be on: aim the crosshair right on the barcode.
5. Clean the scan window, try a different barcode and change the distance. Reading range depends on the scan engine in your configuration.

CauseA modifier key is still on. The orange key switches the number keys to letters, and SHIFT, CTRL and ALT stay on until you press them again. Apps or administrators can also remap keys.

Fix

1. Look at the status bar. An orange icon means the orange (alpha) mode is on, C means CTRL, A means ALT and an up arrow means SHIFT.
2. Press the same key again to switch the mode off. Press CTRL twice to return to normal.
3. If the 3×3 symbol grid stays open, press the Diamond key again to close it.
4. If a key misbehaves in one app only, it has probably been remapped. Ask your administrator.

CauseIf the access point does not broadcast a country code, the MC3400 cannot use channels 12–13 or the 5 GHz channels. Other causes are the wrong security type, a 6 GHz network on an access point that is not Wi-Fi 6E, or weak coverage.

Fix

1. Open Settings › Network & internet › Internet, scroll down and touch Network preferences › Additional Settings. Under Regulatory, touch Country Selection, confirm the warning and select the country where you use the device. This enables all channels for that country even if the access point does not broadcast a country code.
2. Forget the network and join it again. Check the security type (for example WPA2-Personal, WPA3-Personal or WPA2/WPA3-Enterprise) and, for Enterprise networks, the EAP method and certificates.
3. If you use a static IP address, check the IP address, gateway and DNS settings.
4. If drops happen in one area only, ask your network administrator to check coverage there.

CauseAn app or the system has stopped responding, or the internal storage is full.

Fix

1. Press and hold Power and touch Restart. This keeps your data and settings.
2. If you see "memory full" or apps close on their own, uninstall apps you do not use and delete old files.
3. If the device stays frozen, follow the hard reset and reset options in Reset a Zebra Android device. An Enterprise or Factory Reset erases data, so try a restart first.