Siemens Iconos R200: system time resets after every power-off
What happened
Reported in the case: after the XCU backup battery ran flat, the system date fell back to 01.03.1999. After the battery was replaced and the date set through the service software, the clock still would not hold over a night with the system powered down — the count restarted from the moment the date had been entered.
What was checked
- Replaced the XCU backup battery.
- Set the date through the service software from the service PC.
- Set the date and time in the BIOS of the Fluorospot Compact workstation.
- Tried to communicate with the XCU over the COM port.
- Looked for a way to reach the XCU board's own BIOS.
Cause
The engineers concluded that the date set through the service software exists only at the software level, while the hardware clock in the XCU board's own BIOS still holds the old value — at every power-up the board re-reads its CMOS and the software follows it. In this case the conclusion was probable, not confirmed by a completed repair.
The cause is probable and was not fully confirmed.
What was done
The suggested fix, not yet carried out at the time of the case: enter the BIOS of the XCU motherboard and set the hardware clock there. To get a picture, the D320 board is swapped temporarily for an ISA graphics card, with a monitor and PS/2 keyboard connected; the XCU unit is preferably removed and powered on a bench (mains, 220 V as reported). Once the time is saved in the BIOS, the D320 board goes back. As reported, this was a probable fix — the job was still pending.
Safety
Powering a removed control unit on an open bench means exposed live mains wiring: feed it only through a sound supply point with verified protective earth, keep hands clear while energised, and repeat the full electrical safety checks (protective earth and leakage currents) before the unit is returned to clinical use.
Lesson: When a system clock will not persist, the hardware clock must be set in the device's own boot BIOS, not only in the service software, because at every power-up the software clock follows the board's CMOS.
Covered in the course: X-ray Service — Level 2: Fault-Finding →
Written from an anonymised case shared by service engineers. It is not a manufacturer instruction and grants no authorisation. Independent note; names are trademarks of their owners.