Unscrew the two 25 mm screws out of the back panel. The two 25 mm screws are located on the left and right side of the battery cartridges with a Phillips #0 screwdriver.

Lift both cartridge lids so that they stand upright.

Locate the two battery terminals. As you begin to slowly remove the amplifier's back panel, feed the two battery terminals back to the amplifier so that they are no longer inside the battery cartridges.