Here are a few tricks and tools for installing an end pin jack in an acoustic guitar. *** Warning *** This video does not address creating the hole for the jack, but that is the riskiest part of the process. Only someone who knows what they're doing and has the right tools should be allowed to create this hole. It's easy to mess up your guitar. You can guess how I know. The details of pickup installations can be different, but the end pin jack is a very common component.
A quick instructional on how to replace an endpin assembly at the same time preventing the soundpost from falling when removing the strings and bridge. a properly fitted soundpost should not fall over when the strings become loosened but cellos do change with age and climate so there is always that risk.