How to replace battery in the Schiller AT-2 light EKG machine

The battery in the Schiller AT2 is as 12 volt 2.2 AH battery commonly available from R&d batteries, there part number is 5515. To replace it requires disasemble of the unit. Note that you should never disasemble this unit while it is plugged in. Also there are several cable that attach teh top housing to the PC board, and if you are not dillagent about not pulling these vcables apart while disasembling the unit, you can do expensive damage. Bearing that in mind, I would proceed as follows:Turn the unit upside down on top of a towed or other soft surcace to prevent scratching the soft plastic of the upper housing. around the perimeter of the case you will see several screws, i think 8 if i remember correctly. Repmove them and place them in a cup or other container. Grip the top and bottem cases together firmly and flip teh unit back upright. GENTLY lift up the top housing, and VERY CAREFULLY slide it about 3 or so inches to the left. This will expose the battery. just lift it out and replace it with the new one.Take care to reconnect the wires in the same position as teh original battery. Mis wiring the battery will cost you hundreds of dollars. The wires connect via slide on spade connectors. grip them by the connector itself(not the wire going into it) and gently rock it side to side while pulling, it will eventually come off the battery terminal. Resemble the unit in the reverse order. Plug the unit in and fully check it prior to re-installing the screws in the bottom of the unit in case you pulled a cable loose. As an alternative, you can detach the cables from the pc board and place the top cover to the side while replacing the battery, but be VERY careful with the cables. I recommend that you have a qualified individual preform this replacement for you. the cove being removed exposes high voltage, and also presents the risk of expensive damage to your unit.