Panasonic KX-TG7411MEB User manual

© Panasonic Communications Co., Ltd. 2009.
Unauthorized copying and distribution is a violation
of law.
ORDER NO. KM40905922CE
Telephone Equipment
Model No. KX-TG7411MEB
KX-TG7412MEB
KX-TGA740MEB
Expandable Digital Cordless Phone
B: Black Version
(for Mexico)

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
TABLE OF CONTENTS
PAGE PAGE
1 Safety Precautions----------------------------------------------- 4
1.1. For Service Technicians --------------------------------- 4
2 Warning -------------------------------------------------------------- 4
2.1. Battery Caution--------------------------------------------- 4
2.2. About Lead Free Solder (PbF: Pb free)-------------- 4
2.3. Discarding of P. C. Board-------------------------------- 5
3 Specifications ----------------------------------------------------- 6
4 Technical Descriptions ----------------------------------------- 7
4.1. US-DECT Description ------------------------------------ 7
4.2. Block Diagram (Base Unit_Main)---------------------- 9
4.3. Block Diagram (Base Unit_RF Part) -----------------10
4.4. Circuit Operation (Base Unit) --------------------------11
4.5. Block Diagram (Handset)-------------------------------18
4.6. Block Diagram (Handset_RF Part)-------------------19
4.7. Circuit Operation (Handset)----------------------------20
4.8. Circuit Operation (RF Part)-----------------------------24
4.9. Circuit Operation (Charger Unit) ----------------------25
4.10. Signal Route -----------------------------------------------26
5 Location of Controls and Components ------------------27
5.1. Controls -----------------------------------------------------27
5.2. Display ------------------------------------------------------28
6 Installation Instructions ---------------------------------------29
6.1. Connections------------------------------------------------29
6.2. Battery-------------------------------------------------------29
7 Operating Instructions-----------------------------------------31
7.1. Programmable Settings ---------------------------------31
7.2. Error Messages -------------------------------------------34
7.3. Troubleshooting -------------------------------------------35
8 Test Mode ----------------------------------------------------------38
8.1. Adjustment and Test Mode Flow Chart -------------38
9 Service Mode -----------------------------------------------------45
9.1. How to Clear User Setting------------------------------45
10 Troubleshooting Guide ----------------------------------------46
10.1. Troubleshooting Flowchart -----------------------------46
11 Disassembly and Assembly Instructions ---------------57
11.1. Disassembly Instructions -------------------------------57
11.2. How to Replace the Handset LCD -------------------60
12 Measurements and Adjustments---------------------------62
12.1. Things to Do after Replacing IC or X’tal ------------62
12.2. Base Unit Reference Drawing-------------------------63
12.3. Handset Reference Drawing---------------------------64
12.4. Frequency Table ------------------------------------------65
13 Miscellaneous ----------------------------------------------------66
13.1. CPU Data (Base Unit)-----------------------------------66
13.2. CPU Data (Handset)-------------------------------------67
13.3. Explanation of IC Terminals (RF Part)---------------68
13.4. How to Replace the Flat Package IC----------------69
13.5. How to Replace the LLP (Leadless Leadframe
Package) IC------------------------------------------------71
13.6. Terminal Guide of the ICs, Transistors and
Diodes -------------------------------------------------------74
14 Schematic Diagram ---------------------------------------------75
14.1. For Schematic Diagram---------------------------------75
14.2. Schematic Diagram (Base Unit_Main) --------------76
14.3. Schematic Diagram (Base Unit_RF Part) ----------78
14.4. Schematic Diagram (Handset_Main) ----------------80
14.5. Schematic Diagram (Handset_RF Part) ------------82
14.6. Schematic Diagram (Charger Unit) -----------------84
15 Printed Circuit Board ------------------------------------------ 85
15.1. Circuit Board (Base Unit_Main) ---------------------- 85
15.2. Circuit Board (Base Unit_RF Part)------------------- 87
15.3. Circuit Board (Handset_Main) ------------------------ 88
15.4. Circuit Board (Handset_RF Part) -------------------- 90
15.5. Circuit Board (Charger Unit)--------------------------- 91
16 Exploded View and Replacement Parts List ----------- 92
16.1. Cabinet and Electrical Parts (Base Unit) ----------- 92
16.2. Cabinet and Electrical Parts (Handset)------------- 93
16.3. Cabinet and Electrical Parts (Charger Unit) ------- 94
16.4. Accessories and Packing Materials ----------------- 95
16.5. Replacement Parts List--------------------------------- 98

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
1 Safety Precautions
1.1. For Service Technicians
•Repair service shall be provided in accordance with repair technology information such as service manual so as to pre-
vent fires, injury or electric shock, which can be caused by improper repair work.
1. When repair services are provided, neither the products nor their parts or members shall be remodeled.
2. If a lead wire assembly is supplied as a repair part, the lead wire assembly shall be replaced.
3. FASTON terminals shall be plugged straight in and unplugged straight out.
•ICs and LSIs are vulnerable to static electricity.
When repairing, the following precautions will help prevent recurring malfunctions.
1. Cover plastic parts boxes with aluminum foil.
2. Ground the soldering irons.
3. Use a conductive mat on worktable.
4. Do not grasp IC or LSI pins with bare fingers.
2Warning
2.1. Battery Caution
1. Danger of explosion if battery is incorrectly replaced.
2. Replace only with the same or equivalent type recommended by the manufacturer.
3. Dispose of used batteries according to the manufacturer's Instructions.
2.2. About Lead Free Solder (PbF: Pb free)
Note:
In the information below, Pb, the symbol for lead in the periodic table of elements, will refer to standard solder or solder that con-
tains lead.
We will use PbF solder when discussing the lead free solder used in our manufacturing process which is made from Tin (Sn),
Silver (Ag), and Copper (Cu).
This model, and others like it, manufactured using lead free solder will have PbF stamped on the PCB. For service and repair
work we suggest using the same type of solder.
Caution
• PbF solder has a melting point that is 50 °F ~ 70 °F (30 °C ~ 40 °C) higher than Pb solder. Please use a soldering iron with tem-
perature control and adjust it to 700 °F ± 20 °F (370 °C ± 10 °C).
• Exercise care while using higher temperature soldering irons.:
Do not heat the PCB for too long time in order to prevent solder splash or damage to the PCB.
• PbF solder will tend to splash if it is heated much higher than its melting point, approximately 1100 °F (600 °C).
• When applying PbF solder to double layered boards, please check the component side for excess which may flow onto the
opposite side (See the figure below).

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
2.2.1. Suggested PbF Solder
There are several types of PbF solder available commercially. While this product is manufactured using Tin, Silver, and Copper
(Sn+Ag+Cu), you can also use Tin and Copper (Sn+Cu), or Tin, Zinc, and Bismuth (Sn+Zn+Bi). Please check the manufac-
turer's specific instructions for the melting points of their products and any precautions for using their product with other materi-
als.
The following lead free (PbF) solder wire sizes are recommended for service of this product: 0.3 mm, 0.6 mm and 1.0 mm.
2.3. Discarding of P. C. Board
When discarding P. C. Board, delete all personal information such as telephone directory and caller list or scrap P. C. Board.

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
3 Specifications
Note:
• Design and specifications are subject to change without notice.
Note for Service:
• Operation range: Up to 300 m outdoors, Up to 50 m indoors, depending on the condition.
• Analog telephone connection: Telephone Line

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4 Technical Descriptions
4.1. US-DECT Description
The frequency range of 1.91 GHz-1.93 GHz is used. Transmitting and receiving carrier between base unit and handset is same fre-
quency. Refer to Frequency Table (P.65).
4.1.1. TDD Frame Format
4.1.2. TDMA system
This system is the cycles of 10 ms, and has 6 duplex paths, but maximum duplex communication path is 5 because of dummy
bearer use.
In 1 slot 417 µs, the 10 ms of voice data is transmitted.
•2 - Handsets Link
Traffic Bearer
A link is established between base unit and handset.
The state where duplex communication is performed.
Handset doesn't make up duplex in no free RF channels because of interference. (*1)
Dummy Bearer
Base unit sends Dummy-data to the all stand-by state handsets.
Handsets receive that data for synchronization and monitoring request from the base unit.
Base unit doesn't send Dummy bearer in no free RF channels because of interference. (*1)
Note:
(*1) It is a feature under FCC 15 regulation and for interference avoidance.
In the case of checking RF parts, it is better in least interference condition.

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.1.3. Signal Flowchart in the Radio Parts
Reception
A voice signal from TEL line is encoded to digital data "TXDATA" by DSP (IC501) in a base unit.
Then TXDATA goes to RF PART, and it's modulated to 1.9 GHz. The RF signal is amplified and fed to a selected antenna.
As for a handset RF, RF signal is received in two antennas.
RFIC (IC701) compares RF signal levels and selects the antenna to be used. Then RFIC down-converts to 864 kHz IF signal
from RX signal in the selected antenna, and demodulates it to digital data "RXDATA".
DSP (IC501) converts RXDATA into a voice signal and outputs it to speaker.
Transmission
A voice signal from microphone is encoded to digital data "TXDATA" by DSP (IC501) in a handset.
Then TXDATA goes to RF PART, and it's modulated to 1.9 GHz. The RF signal is amplified and fed to a selected antenna.
As for a base unit RF, RF signal is received in two antennas.
RFIC (IC701) compares RF signal levels and selects the antenna to be used. Then RFIC down-converts to 864 kHz IF signal
from RX signal in the selected antenna, and demodulates it to digital data "RXDATA".
DSP (IC501) converts RXDATA into a voice signal and outputs it to TEL line.

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.2. Block Diagram (Base Unit_Main)
KX-TG7411/7412 BLOCK DIAGRAM (Base Unit_Main)
D101
CHARGE_CONTACT
+
-
X501
13.824 MHz
ANT2ANT1
TEL JACK
L1T L1R DCP DCM
DC JACK
RLY
SIDE TONE CIRCUIT
Q161
Q141
BELL DETECT
RLY
BELL
Q111
LIN
LOUT
RF_PART
CID_IN CID_IN
IC501
DSP
INUSE DETECT 2
INUSE DETECT 1
RECEIVE AMP
DCIN 1 DCIN 2
IC331
RESET
POWER_DOWN
VCCIN
VCC
VCCA
VCCPA
INT_1
V_RF
INT_1 5
VCC
IC611
EEPROM
R151,R152 R131, R133
Q171
V_PA
DVCC
SI,SO,CS,
3.3 V REGULATOR
IC321
3.0 V REGULATOR
with RESET
CLK,RST
R371 R372 R373 R374
KEY 1
KEY_C
SW662
SYN_OUT BCLK SYN_EN SYN_CLK SYN_DATA SLOT_CTROL RADIO_EN TXDATA RXDATA RF_RSTN

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.3. Block Diagram (Base Unit_RF Part)
V_PA V_RF DVCC
Note: (*1) Antenna Type: wired dipole antenna KX-TG7411/7412 BLOCK DIAGRAM (Base Unit_RF Part)
PLL 13.824 MHz
IC701
ANT1 (*1)
ANT2 (*1)
Control
Logic
Mixer A/D Demodulator
delta-sigma Modulator
D781 D771
BCLK SYN_OUT SYN_EN SYN_CLK SYN_DATA SLOT_CTROL RADIO_EN TXDATA RXDATA RF_RSTN
Divider
1.5
DSP
IC501

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.4. Circuit Operation (Base Unit)
General Description:
(DSP, EEPROM) is a digital speech/signal processing system that implements all the functions of speech compression, and
memory management required in a digital telephone.
The DSP system is fully controlled by a host processor DSP. The host processor provides activation and control of all that func-
tions as follows.
4.4.1. DSP (Digital Speech/Signal Processing: IC501)
•DTMF Generator
When the DTMF data from the handset is received, the DTMF signal is output.
•Caller ID demodulation
The DSP implements monitor and demodulate the FSK/DTMF signals that provide CID information from the Central Office.
•Digital Switching
The voice signal from telephone line is transmitted to the handset or the voice signal from the handset is transmitted to the Tele-
phone line, etc. They are determined by the signal path route operation of voice signal.
•Block Interface Circuit
RF part, LED, Key scan, Telephone line.
4.4.2. EEPROM (IC611)
Following information data is stored.
•Settings
ex: ID code, Flash Time, Tone/Pulse

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.4.3. Power Supply Circuit
Function:
The power supply voltage from AC adaptor is converted to the desired voltage of each block.
Circuit Operation:
• IC321: 3.0 V Regulator
• IC331: 3.3 V Regulator

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.4.3.1. Charge Circuit
The voltage from the AC adaptor is supplied to the charge circuits.

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.4.4. Reset Circuit
Function:
This circuit is used to initialize the microcomputer when it incorporates an AC adaptor.
Circuit Operation:
When the AC Adaptor is inserted into the unit, then the voltage is shifted by IC331 and power is supplied to the DSP.
The set starts to operate when VCC goes up to 3.0 V or more in the circuit voltage diagram.
Note:
(*1) The initializing time of the DSP chip is 28 ms under normal conditions.

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.4.5. Telephone Line Interface
Telephone Line Interface Circuit:
Function
• Bell signal detection
• ON/OFF hook and pulse dial circuit
• Side tone circuit
Bell signal detection and OFF HOOK circuit:
In the idle mode, Q141 is open to cut the DC loop current and decrease the ring load. When ring voltage appears at the Tip (T)
and Ring (R) leads (When the telephone rings), the AC ring voltage is transferred as follows:
T →L101 →R111 →C111 →Q111 →DSP pin 58 [BELL]
When the CPU (DSP) detects a ring signal, Q141 turns on, thus providing an off-hook condition (active DC current flow through
the circuit). Following signal flow is the DC current flow.
T →L101 →D101 →Q141 →Q161 →R163 →R167 →D101 →L102 →P101 →R
ON HOOK Circuit:
Q141 is open, Q141 is connected as to cut the DC loop current and to cut the voice signal. The unit is consequently in an on-
hook condition.
Pulse Dial Circuit:
Pin 59 of DSP turns Q141 ON/OFF to make the pulse dialing.
Side Tone Circuit:
Basically this circuit prevents the TX signal from feeding back to RX signal. As for this unit, TX signal feed back from Q161 is
canceled by the canceller circuit of DSP.

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.4.6. Parallel Connection Detect Circuit
Function:
In order to disable call waiting and stutter tone functions when using telephones connected in parallel, it is necessary to have a
circuit that judges whether a telephone connected in parallel is in use or not. This circuit determines whether the telephone con-
nected in parallel is on hook or off hook by detecting changes in the T/R voltage.
Circuit Operation:
Parallel connection detection when on hook:
When on hook, the voltage is monitored at pin 86 of IC501. There is no parallel connection if the voltage is
1.65 V or higher, while a parallel connection is deemed to exist if the voltage is lower.
Parallel connection detection when off hook:
When off hook, the voltage is monitored at pin 90 of IC501; the presence/absence of a parallel connection is determined when
the voltage changes by 0.2 V or more.

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.4.7. Calling Line Identification (Caller ID)/Call Waiting Caller ID
Function:
The caller ID is a chargeable ID which the user of a telephone circuit obtains by entering a contract with the telephone company
to utilize a caller ID service. For this reason, the operation of this circuit assumes that a caller ID service contract has been
entered for the circuit being used.
The Caller-ID data from exchange is supplied to the telephone using either method of FSK or DTMF. The method is chosen
according to the exchange of telephone office. This unit is available to receive the data with both methods and displays the
received data on LCD.
• FSK (Frequency Shift Keying) format
• DTMF format
It is the method to send the telephone number of calling party with DTMF to the telephone. DTMF is sent before the first bell sig-
nal.
The data is sent in turn; first the start code, secondly the telephone number of calling party, lastly end code.
The DTMF is chosen from A (1633 Hz and 697 Hz), B (1633 Hz and 770 Hz), C (1633 Hz and 852 Hz) and D (1633 Hz and 941
Hz) as the start code and end code according to the exchange.

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.5. Block Diagram (Handset)
V_PA
V_RF
V_IO
2.7 V
IC374
IC371
IC501
IC541
MIP
MIN
SPP1
LCD BACKLIGHT
SPN
BELL_LIGHT
HSM
HEADSET_DET
SPP2
SPPN
CI
CI
VCCPA
VCCA
VCC
PDN
DSP
RESET
CHG_CTL
CHG_DET
WP, CLK, DATA
KEYSTOROBE_A~E
KEYIN_1~5
Q531
CHARGE
DETECT
CHARGE Q361 D361
Q362, Q364
CHARGE
CONTROL
RST
IC561
DC/DC
CONVERTER
REGULATOR
2.7 V
IC741
REGULATOR
MIC
SP
Headset Jack
CN431
R436/R437
LED561
HEADSET
DETECT
Monitor SP
LCD KEYS
RF part
ANT1ANT2
X501
13.824 MHz
EEPROM
BATTERY
Q561
LCD
BACK
LIGHT
RST
(BELL)
IC372
DC/DC
CONVERTER
IC373
DC/DC
CONVERTER
SYN_OUT
SYN_EN
SYN_CLK
SYN_DATA
SLOT_CTROL
RADIO_EN
TXDATA
RXDATA
RF_RSTN
RF_POWER
KX-TGA740 BLOCK DIAGRAM (Handset)
BL_LED
Q562
LED551-554
(KEY)

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.6. Block Diagram (Handset_RF Part)
V_PA V_RF
(*1) Antenna Type ( difference between base unit and handset in Radio parts)
ANT1: patterned antenna
KX-TGA740 BLOCK DIAGRAM (Handset_RF Part)
ANT2: wired dipole antenna
PLL 13.824 MHz
IC701
ANT1 (*1)
ANT2 (*1)
Control
Logic
Mixer A/D Demodulator
D781 D771
BCLK SYN_OUT SYN_EN SYN_CLK SYN_DATA SLOT_CTROL RADIO_EN
TXDATA
RXDATA RF_RSTN
Note:
delta-sigma Modulator
DSP
IC501
Divider
1.5

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KX-TG7411MEB/KX-TG7412MEB/KX-TGA740MEB
4.7. Circuit Operation (Handset)
4.7.1. Construction
The circuit mainly consists of DSP and RF part as shown in the block diagram.
4.7.1.1. DSP: IC501
Function
• Battery Low, Power down detect circuit
• Ringer Generation
• Interface circuit
RF part, Speaker, Mic, LED, Key scan, LCD, Headset
Initial waves
Note:
(*1) The initializing time of the DSP chip is 20 ms under normal conditions.
4.7.1.2. RF part
Mainly voice signal is modulated to RF, or it goes the other way.
4.7.1.3. EEPROM: IC541
Setting data is stored.
ex: ID code, user setting