Common Issues and How to Fix Them on Your CommBox Classic S4
Running into problems with your CommBox? Here’s a quick guide to common issues that are easy to troubleshoot on your own—plus when to contact CommBox Support.
Applies To
Applies to: Classic S4, Classic S4+
Lock Screen or Settings PIN Forgotten
Issue: You’ve forgotten the lock screen or settings PIN
Solution:
- Read this article first - What to do if you don't know the PIN
-
If still stuck Contact CommBox Support at +61 2 9975 6001 for assistance
Wi-Fi Issues (5 GHz Not Connecting)
Issue: The CommBox can't connect to a 5 GHz Wi-Fi network
Solutions:
-
The Wi-Fi module may not be installed correctly—check that it's securely connected underneath the screen
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Some 5 GHz bands may not be supported—ask your IT administrator to review the network settings
💡 Note: 5 GHz has shorter range and may be blocked by walls or large metal objects. Try a 2.4 GHz network instead.
Stylus Missing or Damaged
Issue: A stylus pen is broken or lost
Solution:
Missing or Unavailable Apps
Issue: An app isn’t showing or can’t be installed
Solutions:
-
The app may not be able to run on Android 11.
-
Note: Apps requiring Google Play Services (e.g. Google Play Store) are not supported
The CommBox Won’t Turn On
No Status Light
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Check that the power cable is firmly plugged in
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If using a power board, ensure it’s switched on
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Make sure the main power switch (next to the AC inlet) is set to the “I” (on) position
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Test the power outlet with another device
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Try a different power cable if available
Red Light On, But Screen is Blank
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Press the Power button on the screen or remote
Green Light On, But Screen is Blank
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Wait 30 seconds after powering on
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Disconnect anything plugged into HDMI OUT ports
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Restart the CommBox
The CommBox Turns Off Unexpectedly
Issue: The screen powers down or enters standby too soon
Solutions:
-
Check the power-off timer in Settings
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Review the auto no-signal power-saving setting
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If connected via RS-232 (e.g. room control system), temporarily disconnect it and test again
Screen Display Problems
Blank Screen (Green Light On)
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Ensure connected computers are powered on and not in standby
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Restart both the CommBox and the computer
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Try different video cables
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Check that the computer is outputting a supported resolution (recommended: 3840×2160 or 1920×1080)
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Ensure the computer's external display port is enabled
“No Signal” Message
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Confirm the computer is connected to the correct input
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Make sure the input source selected on the CommBox matches the port used
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Enable external display output on your laptop
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Use only CommBox-recommended video cables
Distorted, Flickering, or Dim Image
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Switch to another input, then switch back
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Restart the CommBox and any connected devices
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Confirm the resolution and refresh rate on your computer match supported settings
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Replace or test with new video cables
- If these tips do not resolve it - contact CommBox Support.
Bright Spots or Colour Issues
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Try adjusting the image mode in Settings > Image
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Small colour variation is normal between side-by-side displays
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If using VGA, test with another cable or source
- If these tips do not resolve it - contact CommBox Support.
Image Shifted or Cropped
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Adjust video output settings on your computer (zoom, crop, overscan)
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Use a darker background instead of black
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If using multiple monitors, try duplicating the display or setting the CommBox as the only screen
Image Doesn't Fill the Screen
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Adjust the overscan or scaling settings on the connected device
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Make sure the output resolution is supported by the CommBox
No Video from USB-C
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Confirm the device supports CommBox Port Alternate Mode via USB-C
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Look for the Thunderbolt logo—if missing, full video+touch may not be supported
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Use a cable marked for SuperSpeed (5 Gbps or higher) with the USB logo
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Replace the cable if not compliant
Still Need Help?
📩 Log a support ticket or call +61 2 9975 6001. If you want faster support remember to provide video or photographic evidence of the issue.