Panasonic KX-TCD755RUS Service Manual ▷ View online
6 DISASSEMBLY INSTRUCUTIONS
6.1. Disassembly of Base Unit and Handest
Shown in Fig.-
To Remove
Remove
1
Lower Cabinet of Base Unit
Screws (2.6 × 10)..........(A) × 2
2
Main P.C. Board of Base Unit
Screw(2.6 × 10)............(A) × 1
3
Charge wire solder
4
Rear Cabinet of Handset
Screws (2 × 8)...............(B) × 2
5
Main P.C. Board of Handset
Screws (2 × 6)...............(C) × 2
13
KX-TCD755RUS
6.2. Assembly the Receiver LCD and PCB
Fit RECEIVER SPACER onto back of RECEIVER, ensure SPACER does not touch leads.
Fit RECEIVER into recess, ensuring leads are fed through LCD HOLDER and under moulding.
Fit RECEIVER into recess, ensuring leads are fed through LCD HOLDER and under moulding.
Remove backing tape from the back of RECEIVER NET.
Fit RECEIVER NET on top of RECEIVER as shown (Sticky side down).
Fit RECEIVER NET on top of RECEIVER as shown (Sticky side down).
14
KX-TCD755RUS
Fit LCD ASSEMBLY onto HANDSET COMPLETED BOARD by fitting FPC cable from LCD ASSEMBLY into connector on
HANDSET COMPLTED BOARD.
Remove backing from RECEIVER SPACER.
Clip LCD ASSEMBLY onto HANDSET COMPLETED BOARD and press RECEIVER SPACER in secure.
HANDSET COMPLTED BOARD.
Remove backing from RECEIVER SPACER.
Clip LCD ASSEMBLY onto HANDSET COMPLETED BOARD and press RECEIVER SPACER in secure.
Solder leads from RECEIVER onto HANDSET COMPLETED BOARD, ensuring leads are in position shown. (RED lead at top
BLACK lead at bottom)
Soldering temperature must be 360± 20 for less than 3 seconds.
Remove LCD protective sheet before fitting into UPPER CABINET ASSEMBLY.
BLACK lead at bottom)
Soldering temperature must be 360± 20 for less than 3 seconds.
Remove LCD protective sheet before fitting into UPPER CABINET ASSEMBLY.
15
KX-TCD755RUS
7 CIRCUIT OPERATION (BASE UNIT)
Audio
Hook
Switch
Switch
16kHz
Filter
Filter
Bridge
Rect.
Rect.
A/D
D/A
Analog
Front End
Front End
Buzzer
CPU
HOOK
RXAF
TXAF
CHARGE PULSE
DSP
BMC
Speech Encoding
Speech Decoding
RF
Interface
Interface
Burst Building
Burst Decoding
ADPCM
Codec Filter
Codec Filter
EEPROM
IC9
IC9
SDA
SCL
SYRI
RSSI
ANT2
SYEN
SYEN
ANT1
RXDA
TXDA
J2
J1
IC6
3.3V
Reg.
Reg.
2.65V
Reg.
Reg.
3.3V
2.65V
VUNREG
63
64
43
37
37
71
95
48
15
8
8
46
20
99
20
99
100
10
5
6
13
RF
Mod
Mod
20
11
12
1
35
17
12
1
35
17
44
37
CHARGE
CONTACT
CONTACT
28
25
XTAL
10.368
MHz
MHz
Fig. 17
KX-TCD755RUS BLOCK DIAGRAM (BASE UNIT)
ADDRESS
DATA
CTRL
Flash
PROM
IC5
PROM
IC5
A0..
A18
A18
D0..
D7
D7
89
30
DTXAF
DTXAF
42
40
BBIC
Interface
Interface
7.1. The Base - Band Section
7.1.1. Introduction (See Fig. 17)
The base-band section consists of a base-band integrated circuit (BBIC), a Flash PROM and an EEPROM, clock generation,
locator key, factory serial port, buzzer circuit and audio paths both TX and RX.
locator key, factory serial port, buzzer circuit and audio paths both TX and RX.
7.1.2. The Base - Band Integrated Circuit (BBIC)
The PMB7728X (IC6) is a Universal Fixed Part Controller (UFC) designed to handle all the audio, signal and data processing
needed in a DECT base unit. It contains a "burst mode controller" which takes care of DECT specific physical layer and radio
section control. It also contains an ADPCM codec filter used for speech encoding and decoding in the DSP section, a general
purpose microcontroller, various other ADC´s, DAC´s, timers and power control circuitry.
The BBIC interfaces to its external PROM (IC5) via a data/address/control bus. It connects to the EEPROM via a serial
interface, and a second serial interface is used during manufacture and service to connect to an external computer.
needed in a DECT base unit. It contains a "burst mode controller" which takes care of DECT specific physical layer and radio
section control. It also contains an ADPCM codec filter used for speech encoding and decoding in the DSP section, a general
purpose microcontroller, various other ADC´s, DAC´s, timers and power control circuitry.
The BBIC interfaces to its external PROM (IC5) via a data/address/control bus. It connects to the EEPROM via a serial
interface, and a second serial interface is used during manufacture and service to connect to an external computer.
7.1.3. FLASH PROM (See Fig. 18)
The 2 Mbit (IC5) Flash PROM contains the operational firmware for the microcontolloer. It is interfaced to the
data/adress/control bus using address lines A0 to A18, data lines D0 to D7, and chip select (pin 30), output enable (pin 32), and
write (pin 7).
data/adress/control bus using address lines A0 to A18, data lines D0 to D7, and chip select (pin 30), output enable (pin 32), and
write (pin 7).
7.1.4. EEPROM (See Fig. 18)
The electrically erasable PROM AT24C128N-10S1(IC9) is used to store all the temporary operating parameters for the base
(see EEPROM LAYOUT). It uses a two-line serial data interface with the BBIC, with bi-directional data on pin 5 (TP104), and
clock on pin 6 (TP103).
(see EEPROM LAYOUT). It uses a two-line serial data interface with the BBIC, with bi-directional data on pin 5 (TP104), and
clock on pin 6 (TP103).
7.1.5. Clock Generation (See Fig. 18)
A single clock generator in the BBIC uses an external crystal X1 to derive all clock frequencies used in the base. The crystal
is tuned to the exact frequency of 10.368 MHz during manufacture.
The BBIC provides a reference clock signal SYRI (pin 20, TP101) which is used to drive the PLL circuitry in the RF module. The
basic data rate for TXDA (pin 15) and RXDA (pin 8) is 1.152 Mbits/s, which is 10.368MHz divided by 9.
is tuned to the exact frequency of 10.368 MHz during manufacture.
The BBIC provides a reference clock signal SYRI (pin 20, TP101) which is used to drive the PLL circuitry in the RF module. The
basic data rate for TXDA (pin 15) and RXDA (pin 8) is 1.152 Mbits/s, which is 10.368MHz divided by 9.
16
KX-TCD755RUS
Click on the first or last page to see other KX-TCD755RUS service manuals if exist.