RTC (inside IC604). At this time, the voltage at pin F17 of the IC604
is +3.3V. When the power switch is turned OFF, the BAT600
supplies power to RTC through D602. The voltage at pin F17 of
IC604 is about +2.5V. When the power switch is OFF and the
voltage of +3.3V decreases, pin F17 of RTC (IC604) becomes
roughly the same voltage as the battery voltage. RTC goes into
the backup mode, in which the power consumption is lower.
Points to notice when replacing the battery
When the backup battery becomes low or the backup function is turned off for repairing,
recover the backup power supply following the procedure described below.
(1) Replace the battery and IC. J600 should be removed beforehand.
(2) Short the both ends of C762. (Ex. Pinch them with tweezers.)
(3) Connect terminals of J600 with solder.
(4) Short the both ends of C762 again. (Ex. Pinch them with tweezers.)
(5) Make sure that the voltage of 3.3V/BATT test land is more than 2.7 V.
Digital Unit component view
194
To Next Page
Loading...
