Read Panasonic KX-NT321RU (serv.man2) Service Manual online
6
KX-NT321RU
4.2.
Circuit Operations
4.2.1.
CPU (IC1)
The DSP, MAC, CODEC and the CPU are built into the VoIP (IC1).
The FLASH (IC2) and the SDRAM (IC3) are connected to the CPU. The contents of the FLASH are expanded to the SDRAM at
start-up. It also stores each setting.
If the LCD is not displayed in the operation but there is no problem on the LCD, then the failure of the CPU system memory (IC2
and IC3) should be considered.
The FLASH (IC2) and the SDRAM (IC3) are connected to the CPU. The contents of the FLASH are expanded to the SDRAM at
start-up. It also stores each setting.
If the LCD is not displayed in the operation but there is no problem on the LCD, then the failure of the CPU system memory (IC2
and IC3) should be considered.
4.2.2.
LCD Circuit
LCD data are output from pin 138 of IC1 to LCD module.
IC12 is an inverter for a charge pump circuit which outputs the voltage necessary for LCD driving.
LCD contrast is set by electronic volume - IC1 - pin142 and pin143.
KX-NT321 uses a 16 digits x 1 lines LCD.
IC12 is an inverter for a charge pump circuit which outputs the voltage necessary for LCD driving.
LCD contrast is set by electronic volume - IC1 - pin142 and pin143.
KX-NT321 uses a 16 digits x 1 lines LCD.
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