If LabQuest is displaying a plain blue screen with "Vernier" written on the far right, then try the following:
1. Connect LabQuest to a computer using the USB cable and open Logger Pro on your computer. Logger Pro should see the LabQuest, and the LabQuest screen should change to the double-arrow screen. You should also be able to connect sensors and collect data in Logger Pro.
2. After verifying Step 1, disconnect the LabQuest. It will return to the plain screen displaying 'Vernier' text. Hold the power button down for 3 seconds to turn the unit off, wait 5 seconds, then turn the unit back on. It may take longer to boot up than usual.
3. Once LabQuest displays the LabQuest App (i.e., the meter screen displaying the File and Sensors menus), reboot the LabQuest by selecting Home, Control Panel, and Reboot. After rebooting, the LabQuest should display the LabQuest App again and work properly. In most cases, this is all that is needed.
4. If LabQuest still displays the plain screen after Step 2 or Step 3, you will need to perform a 30-second hard reset. To do this, turn the LabQuest over and use the stylus to press and hold the reset button (a small gray button located just below where the stylus is stored) for 30 seconds. After pressing for 30 seconds, release the button. The unit should reboot, but it may take longer to boot up than usual.
5. Once LabQuest displays the LabQuest App (e.g., the meter screen displaying the File and Sensors menus), reboot the LabQuest by selecting Home, Control Panel, and Reboot. After rebooting, the LabQuest should display the LabQuest App again and work properly.
6. If LabQuest instead displays the plain screen after Step 4 or Step 5, then reload the firmware. Since you can't get to the system info dialog to reload the firmware, you'll need to force the firmware on by following the steps listed under "Recovery instructions" here:
TIL 2370: My original LabQuest keeps rebooting, is stuck on a screen with text, or stuck on the LabQuest logo screen.
7. If you are still having problems, please contact Vernier technical support to set up a repair.