DSC-F1 (serv.man2) - Sony Digital Camera Service Manual (repair manual). Page 7

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The input voltage from the AC adapter is supplied from the DC jack. The power supply voltage passes through the line

filter (LF001) and fuse to become the UNREG voltage.

Circuits causing the malfunction can be separated from the blown fuse. F001 of the DD board is for the PWM controller

(IC004), 3.1V voltage, and LCD transformer, while F002 is for the 5V voltage and charge circuit. F003 is for the backlight and
2.8V voltage.

The plus side of the lithium ion rechargeable battery is connected to the plus side of the DC jack. If the DC jack is not

connected to anything, the minus side (LIBATT) will contact the GND at the contact point inside the DC jack (See Fig. 2).
However, if a plug is connected to the DC jack, the contact point inside the DC jack will separate, and the minus side will
separate from the GND.

• When connecting the AC adapter to the outlet

The unit operates on the AC adapter voltage.
When the charge circuit is operating, the minus side of the rechargeable battery is connected to the GND via the charge

circuit, and a current flows to the rechargeable battery.

• When no connecting the AC adapter to the outlet

In this state, the minus side of the rechargeable battery is connected to the GND via the Q002 collector-base (functions as

a diode), and current flows to the minus side of the rechargeable battery from the GND.

Consequently, because a low rechargeable battery voltage is detected due to the diode voltage included, the voltage is taken

as to have dropped even if there is still rechargeable battery power, and the operating time shortens.

When not connecting the AC adapter to the outlet, be sure to disconnect the DC plug.