DSC-F1 (serv.man2) - Sony Digital Camera Service Manual (repair manual). Page 12

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• Starting the LCD

When the main microprocessor is started, the LCD and camera section are started according to the mode started by

serial data communication with the HI microprocessor.

When the H signal of the LCD ON signal (Pin !£ of IC301) of the H microprocessor is input to the PWM controller

(Pin @ª of IC004), Q030 is switched by the PWM output from the OUTPUT-3 terminal (Pin %§), and the UNREG voltage
is supplied to the transformer.

Various voltages corresponding to the number of windings are output from the transformer.
Q040 of the DD board is turned ON by the LCD signal, Q039 is turned ON, and +5V for the LCD is output.

• Starting the camera block

Q048 of the DD board is turned ON by the H output of the CAMON signal (Pin !™ of IC301) from the HI microprocessor,

Q046, Q049, and Q045 are turned ON, and +5V and –7.5V for the camera block are output.

• Transformer output

Voltage is output according to the number of windings of the transformer.
WPin 5 ........ –18V REG (LCD)

WPin 6 ........ –7.5V REG (LCD, camera section)

WPin 7 ........ +11V REG (LCD)

WPin 8 ........ +15V REG (Camera section)

• –18V REG

The output of Pin 5  of T001 is rectified, and LCD-18V is output by the Q51 and Q53 regulator circuits with

LCD+11V as the reference voltage.

• –7.5V REG

The output of Pin 6  of T001 is rectified, and LCD-7.5V is output by the Q42 and Q43 regulator circuits with

LCD+11V as the reference voltage.

• 11V REG

The output of Pin 7 of T001 is rectified, and fed back to Pin #¢ of IC004. Q030 is controlled by the PWM output from

Pin %§ of IC004 so that this voltage will always remain 11V even if the UNREG voltage is changed.

• 15V REG

The output from Pin 8 of T001 is rectified, and CAM +15V is output by the Q041 and Q044 regulator circuits with

CAM+5.0V as the reference voltage.

If the minus voltage such as –7.5/18V is not output normally, the Q052 base voltage resistance-divided rises and the

protection circuit turns ON. This is detected as a voltage defect by the PWM controller (Pin !£ of IC004 becomes L). In
this case, the PWM controller will stop operating.