Sound Devices has heard from a few mixer customers experiencing difficulty removing AA batteries from the battery compartment of a field mixer, specifically the first two inserted cells. There are two reasons this would occur:
Oversized AA Batteries
Rechargeable battery manufacturers are pushing the limits of AA battery size. Some batteries have diameters out of specification, especially when they are at elevated temperature during operation or fresh off a charger. Oversized cells can become stuck in the battery tube of a Sound Devices mixer, especially if they have plastic coatings that adds to the overall diameter. Sound Devices mixers accept AA batteries that are within spec and do not accommodate oversized batteries. The inner diameter of the mixer's battery tubes are 0.6-inch +/- 0.005-inch. If you have a battery that does not easily fit in the tube Do Not force it into the tube! If you already have a battery stuck in the tube your mixer may need servicing.
442 Battery Compartment
The battery compartment of the 442 is made up of two machined-plastic segments threaded together to form the battery tube assembly. At the joint where these two tubes meet, the ID (inner diameter) can be reduced if excess force is used to mate the two parts. A small ridge develops, making some battery types—specifically those with battery testers and oversized AA's—difficult to remove. The battery gets stuck at the internal junction. Sound Devices manufacturing processes have changed to prevent this issue from occurring on late-model 442 mixers, but a small number of older 442 mixers in the field can exhibit this condition. Mixers that don't exhibit the problem will not in the future. 442 mixers with serial numbers greater than 030102094XXX will not experience the problem.
How to Remove Stuck Batteries
It is possible that rechargeable batteries that have swelled due to heat will shrink when returned to room temperature. Additionally, you can cool the unit in a refrigerator to force the cells to a lower temperature, then gently tap the mixer to attempt to free any stuck cells. If they are hopelessly stuck, contact us.
If your mixer is one of the few units that has batteries stuck in the tube, contact Sound Devices at (608) 524-0625 for a return authorization number. If your mixer has a serial number below 030102094XXX Sound Devices will replace the battery tube, test the mixer, and return it via UPS Ground at our expense.