Read Panasonic KX-DT521RU Service Manual online
7
KX-DT521RU/KX-DT521RU-B
4.2.
Circuit Operations
4.2.1.
LCD Circuit
LCD data are output from pin 66 of IC410 to LCD module.
LCD contrast is set by electronic volume in LCD module.
VCC33 (+3.3V) of the power supply voltage is doubled in the LCD module and used as LCD driving voltage (approx. 6.5V(KX-
DT521))
The driving voltage is observed between pin 12 (V0) and pin 13(XV0) of CN460.
LCD contrast is set by electronic volume in LCD module.
VCC33 (+3.3V) of the power supply voltage is doubled in the LCD module and used as LCD driving voltage (approx. 6.5V(KX-
DT521))
The driving voltage is observed between pin 12 (V0) and pin 13(XV0) of CN460.
The lighting of the backlight is controlled by Q460.
The power of the backlight is output from DOUT4V5 of IC410.
The power of the backlight is output from DOUT4V5 of IC410.
4.2.2.
Reset Circuit
IC410 (DCX81) is reset internally by itself when power is supplied.
Reset Signal is output from IC410 and input into IC300 (pin 1) ,CN460 (pin 5) and IC205 (pin 41).
Reset Signal is output from IC410 and input into IC300 (pin 1) ,CN460 (pin 5) and IC205 (pin 41).
6
IC410
DCX81
R423
DG
C362
DG
1
IC300
RSTN
10
R424
DG
CN400
10
5
ASIC_RST
41
DG
94
CN460
5
/RES
LCD_RS
VCC33
5
EXGPIO9
GPIO15
EXGPIO8
VCC1
VCC2
VCC3
VCC3
VCC4
94
79
73
ASIC1
LCD
RESET
ASIC2
Main PCB
CN205
Ope PCB
IC205
C243
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