The preferred way to replace the AC adapter port on an original LabQuest is to replace the UAP (USB, Audio, Power) circuit board in the unit. Unfortunately, we no longer have replacement boards available as some component parts that make up the board are no longer available.
It is possible to replace just the power jack, but that can be tricky, and if not done right, additional damage can be done to the board. Because of this, we no longer make this repair ourselves. If this is something you want to try, it should only be done by someone that is pretty good at soldering electronic components. Below is information on getting the component you need for the repair.
Manufacturer: Mouser Electronics
Part Number: KLDX-SMT-0201L-BTR
Web Site: https://www.mouser.com/ProductDetail/Kycon/KLDX-SMT-0201L-BTR?qs=B0WMqhnxtbIxhhpe5PwhtQ%3D%3D
If replacing the adapter port is not for you, use a different LabQuest unit to charge the battery, switching batteries between units as needed. See
How do I remove or replace an original LabQuest battery?
NOTE: This is certainly not ideal and we only suggest this as a last resort as it is easy to damage the battery connector on a LabQuest, which is also something not easily repaired.