This information pertains to LabQuest 2 and LabQuest 3.

If you have an original LabQuest, see this article.

If LabQuest 2 or LabQuest 3 won’t turn on at all and the screen remains dark, there could be a hardware problem and it may need to come in for repair.

To check LabQuest, plug it into the LabQuest Power Supply* and follow these steps.

  1. Verify that the power outlet has power by plugging in a device that you know works properly. (Many labs have old wiring and breakers that easily trip.)
  2. Try to determine if the power supply works. If you have multiple LabQuest units and multiple power supplies, try different combinations. You will know that the power supply works if the LabQuest unit turns on and the battery icon displays a lighting bolt when the unit is connected to power. See
    What does the battery icon on my LabQuest 2 mean?
    What does the battery icon on my LabQuest 3 mean?
  3. Look inside the LabQuest power jack port to see if a pin is centered in the hole. If that pin is missing, the unit will not receive power and it will need to come in for repairs. (LabQuest 2 units may still charge in a charge station through the serial port.)
  4. Try swapping the battery from a fully charged LabQuest into the one that won’t turn on. If it turns on with a different battery, then the issue might be related to the power adapter or charge circuit.
  5. If the LabQuest still will not turn on, it will need to come in for repair. Please contact Vernier Technical Support for a Return Merchandise Authorization.

Note: If you only have one LabQuest device and one AC adapter, and therefore can’t determine which one is not working, then they will both need to come in for repair. If you can isolate the problem to just one or the other, only the broken item needs to come in for repair.

*The LabQuest Power Supply is 5 V, center positive, and 1.5 or 2.5 amps. The original LabQuest and LabQuest 2 use the same power adapter, but we’ve shipped several models of that adapter over the years so they may not look identical. LabQuest 3 uses a different power supply that can be used with any model LabQuest. LabQuest® Power Supply (LQ3-PS)

See also
I have trouble getting my LabQuest 2 to turn on/start up. (flowchart)
Why does LabQuest 2 screen flash white, and then black, when I turn it on?