I'm looking at CONN4, which provides the input for the 9V DC power supply, and I'm not seeing any way that it is isolating the 9V battery from the 9V DC power. From looking at the
KLDX_0202 Datasheet, pins 2 and 3 will always be connected. That means that if there is a battery attached, and the 9V DC power supply is plugged it, 9V will be placed across the battery. The battery is likely providing
less than 9V, and the power supply will therefore push current into the battery. If the battery is a primary cell, this is a Bad Thing.
Is there something I'm missing?