Before starting, turn the contrast wheel to the darkest setting.
- Open the S4 programmer by unscrewing the four screws in each corner.
- Separate the two halves of the case, making sure that the main PCB board stays with the front half on the S4.
- Unplug the battery lead by gently pulling the plug out of the lower socket on the PCB and remove from the back half of the S4.
- Insert the replacement battery pack into the back half of the S4. Make sure that the lead is in the top left corner of the battery. Ensure that once the battery is fitted, the lead is trapped between the foam in the case and the battery pack.
- If the contrast wheel has been removed while changing the battery, make sure that the notch on the contrast wheel is pointing towards the bottom of the programmer and that it can not turn any further anti-clockwise.
- Put the two halves of the case back together, making sure that all the leads are curled together above the RAM chip. Screw the S4 together, turn on and start the standard charging procedure.