Symbol FR6000 CMOS Replacement Battery 3V 200mAh

Symbol FR6000 — 3V Lithium CMOS Backup Battery

This is a 3V, 200mAh lithium coin cell replacement for the Symbol FR6000 mobile computer. It backs the RTC circuit and SRAM, keeping the system clock and stored settings intact when main power is removed or swapped. At 20.00 × 20.00 × 3.80mm, it fits the FR6000 motherboard socket directly.

• FR6000 CMOS retention circuit: The FR6000 uses a dedicated CMOS cell to power its real-time clock and volatile SRAM independently of the main battery. When the cell drops below 2.8V, the RTC loses its reference voltage and the SRAM can no longer hold configuration data between power cycles.
• Bench tested on actual hardware: We measured open-circuit voltage before shipping — cells leave our warehouse above 2.9V. Under the low-microamp draw typical of an RTC retention circuit, the cell stabilises at 3.0V within the first hour of installation.
• Post-installation clock correction: After fitting this cell, navigate to the FR6000 system settings and manually set the correct date and time before resuming normal operation. The CMOS cell powers the RTC circuit, and any interruption resets the clock to a factory default value that the new cell cannot self-correct.

Clock resetting to a default date after every main battery swap on the FR6000

The FR6000 relies on the CMOS cell to keep the RTC running during the gap between removing the main battery and inserting a new one. If the CMOS cell is below 2.8V retention voltage, even a two-second interruption clears the clock. A depleted cell cannot bridge that gap, so the RTC reverts to its factory default date on every swap. Replacing the CMOS cell and then setting the correct system time in device settings resolves this permanently.

CMOS checksum error appearing on FR6000 boot

A checksum error at boot means the device detected that stored CMOS values no longer match the checksum written when settings were last saved — a clear sign the cell dropped too low to maintain SRAM retention. This is a different symptom from a drifting clock: here, the configuration itself is corrupted, not just the time. Fitting a fresh 3V cell and re-entering all device settings clears the error. Confirm the new cell reads at or above 2.9V with a multimeter before closing the housing.