Vernier Software and Technology
Vernier Software & Technology
Tech Info Library

LabQuest blue power button LED ring stays on, but the screen is black.

Original LabQuest
This information pertains to the original LabQuest.
If you have LabQuest 2, see LabQuest 2 FAQs

There are a few possible causes to this problem:

1. The unit may be asleep.
In the LabQuest App v1.3 and newer, there is a power management feature that will turn the screen off after 5 minutes of idle time. To turn the screen back on, simply tap the screen, press a key, or press the power button. If you do not like this power-saving feature, adjust the power management. Tap the Home icon, choose Control Panel, and then select Light & Power.

2. LabQuest has crashed.
If this fails to resolve the issue, it may be necessary to reset the unit. Reset the LabQuest only if all other attempts fail. For more information, see:
TIL 1777: How do I reboot or reset a LabQuest?

3. Extremely low battery caused a crash while shutting down.
It is possible for the battery level to get extremely low and there to be too little power to restart the unit, even when plugged into AC. (In this state, the battery will not charge).
When this happens, hold down the reset button on the back of the LabQuest for 15 seconds. (The reset button effectively just disconnects power). If this does not work, it may be necessary to physically disconnect to battery (see TIL 2189: How do I remove or replace a LabQuest battery?). Either of these will force the LabQuest to completely shut down. After all lights are off, wait 60 seconds, then re-connect the unit to AC power. If the battery is completely discharged, it may take as long as two minutes before the screen lights and the unit begins it 2 1/2 minute boot-up cycle. Charge the unit for several hours before trying to use it without AC.

To prevent this problem: Once the LabQuest has been reset, make sure you are using LabQuest App version 1.5.1 or newer. Version 1.5 was especially prone to this problem. The free update is available at:

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