Sangean SG-622 (V1) - Manual (Page 4)

Power Supply
11
Alternative Power Supply
9
The Battery Compartment is located at the back of the unit.
Open it by sliding the cover in direction of the OPEN. Insert 3
AA (UM-3) size batteries in compartment, then replace the
cover.
This unit is fitted with a 4.5V DC power socket which will accept a
4.5V 150 mA DC external main adaptor with central negative pin
(Adaptor not included). When in use, the adaptor will automatically cuts
out the batteries.
4