Chapter 2. CPU Features & SpecificationsGFK-2222AD April 2018 57Replacement of Real-Time Clock Battery on CPE400Figure 15: Location of RTC battery on CPE400The CPE400 is shipped with a real-time clock (RTC) battery installed on an internal circuit board (seeFigure 15). This battery will need to be replaced periodically by a qualified service technician. Typically,no action is required during initial installation.Should the RTC battery fail, the CPU date and time will be reset to 12:00 AM, 01-10-2000 at start-up. TheCPU operates normally with a failed or missing RTC battery; however, the initial CPU time-of-day (TOD)clock information will be incorrect.There are no diagnostics or indicators to monitor RTC battery status. The RTC battery has an estimatedlife of 5 years and must be replaced every 5 years on a preventative maintenance schedule.To replace a depleted battery:1. Power down the CPE400.2. Disconnect the external cables attached to the CPE400, labelling each for later reconnection.3. Remove the CPE400 from its installed location.4. Take the CPE400 to a clean environment.5. Remove the DIN-rail or panel-mount adaptor plate, as applicable.6. Place the CPE400 on a workbench so that the heat-sink adjacent to the GE logo on the front panel isfacing up.7. With ESD protection in place, remove the four screws holding the upper side heat sink in place.8. Remove the heat sink. This exposes the circuit board, connectors and coin battery shown in Figure15.9. Take care to collect any thermal pads that may have been dislodged. These will be needed duringreassembly.
