KX-TG6811RUB, KX-TG6811RUM, KX-TG6812RUB, KX-TG6821RUB, KX-TG6821RUM, KX-TG6822RUM, KX-TG6881RUB, KX-TG6891RUB, KX-TGA681RUB, KX-TGA681RUM, KX-TGA20EXB - Panasonic Telephone Service Manual (repair manual). Page 3

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1 Safety Precautions----------------------------------------------- 5

1.1. For Service Technicians --------------------------------- 5

2 Warning -------------------------------------------------------------- 5

2.1. Battery Caution--------------------------------------------- 5
2.2. About Lead Free Solder (Pbf: Pb free)--------------- 5

2.2.1. Suggested PbF Solder ------------------------------ 6

2.3. Discarding of P.C. Board--------------------------------- 6

3 Specifications ----------------------------------------------------- 7
4 Technical Descriptions ----------------------------------------- 8

4.1. Block Diagram (Base Unit) ------------------------------ 8
4.2. Circuit Operation (Base Unit) --------------------------- 9

4.2.1. Outline --------------------------------------------------- 9

4.3. Block Diagram (Base Unit RF Part)------------------10
4.4. Circuit Operation (Base Unit) -------------------------- 11

4.4.1. BBIC (Base Band IC: IC501) --------------------- 11
4.4.2. Flash Memory (IC601) (for KX-TG6821

only) ----------------------------------------------------- 11

4.4.3. EEPROM (IC611) ------------------------------------ 11
4.4.4. Telephone Line Interface---------------------------12
4.4.5. Power Supply Circuit--------------------------------13

4.5. Block Diagram (Handset)-------------------------------15
4.6. Circuit Operation (Handset)----------------------------16

4.6.1. Outline --------------------------------------------------16
4.6.2. Power Supply Circuit/Reset Circuit--------------16
4.6.3. Charge Circuit ----------------------------------------16
4.6.4. Battery Low/Power Down Detector--------------16
4.6.5. Speakerphone ----------------------------------------16

4.7. Behavior of Electric Power Failure -------------------17

4.7.1. Supply from handset --------------------------------17
4.7.2. Supply from large capacitor -----------------------17

4.8. Signal Route -----------------------------------------------18

5 Location of Controls and Components ------------------20
6 Installation Instructions ---------------------------------------20
7 Operating Instructions-----------------------------------------20

7.1. For Service Hint-------------------------------------------20

8 Service Mode -----------------------------------------------------21

8.1. Engineering Mode ----------------------------------------21

8.1.1. Base Unit ----------------------------------------------21
8.1.2. Handset ------------------------------------------------23

8.2. EEPROM LAYOUT (Handset)-------------------------25

8.2.1. Scope ---------------------------------------------------25
8.2.2. Introduction --------------------------------------------25
8.2.3. EEPROM contents ----------------------------------25

8.3. How to Clear User Setting------------------------------26

8.3.1. Resetting both base unit and handset----------26
8.3.2. Resetting only handset -----------------------------26

9 Troubleshooting Guide ----------------------------------------27

9.1. Troubleshooting Flowchart -----------------------------27

9.1.1. Check Power------------------------------------------28
9.1.2. Check Battery Charge ------------------------------29
9.1.3. Check Link---------------------------------------------30
9.1.4. Check the RF part -----------------------------------33
9.1.5. Check Handset Transmission --------------------36
9.1.6. Check Handset Reception-------------------------36
9.1.7. Check Caller ID --------------------------------------36
9.1.8. Bell Reception ----------------------------------------37
9.1.9. Check TAM Operation (for KX-TG6821

only) -----------------------------------------------------37

9.1.10. Power failure mode --------------------------------- 38

9.2. Troubleshooting by Symptom (Base Unit) --------- 39

9.2.1. Check Point (Base Unit) --------------------------- 39

9.3. Troubleshooting by Symptom (Handset) ----------- 41

9.3.1. Check Point (Handset) ----------------------------- 41
9.3.2. Troubleshooting for Speakerphone ------------- 44

10 Disassembly and Assembly Instructions--------------- 45

10.1. Disassembly Instructions------------------------------- 45

10.1.1. Base Unit ---------------------------------------------- 45
10.1.2. Handset ------------------------------------------------ 49
10.1.3. Charger Unit ------------------------------------------ 50

10.2. How to Replace the Handset LCD------------------- 51

11 Measurements and Adjustments -------------------------- 52

11.1. Equipment Required ------------------------------------ 52
11.2. The Setting Method of JIG (Base Unit) ------------- 52

11.2.1. Connections ------------------------------------------ 52
11.2.2. How to install Batch file into P.C. ---------------- 53
11.2.3. Commands-------------------------------------------- 53

11.3. Adjustment Standard (Base Unit) -------------------- 54

11.3.1. Bottom View ------------------------------------------ 54

11.4. The Setting Method of JIG (Handset)--------------- 55

11.4.1. Connections ------------------------------------------ 55
11.4.2. How to install Batch file into P.C. ---------------- 56
11.4.3. Commands-------------------------------------------- 56

11.5. Adjustment Standard (Handset) ---------------------- 57

11.5.1. Component View ------------------------------------ 57

11.6. Things to Do after Replacing IC or X'tal ------------ 58

11.6.1. How to download the data ------------------------ 58

11.7. RF Specification ------------------------------------------ 60

11.7.1. Base Unit ---------------------------------------------- 60
11.7.2. Handset ------------------------------------------------ 60

11.8. How to Check the Handset Speaker or

Receiver ---------------------------------------------------- 61

11.9. Frequency Table (MHz)--------------------------------- 61

12 Miscellaneous---------------------------------------------------- 62

12.1. How to Replace the Flat Package IC --------------- 62

12.1.1. Preparation-------------------------------------------- 62
12.1.2. How to Remove the IC ----------------------------- 62
12.1.3. How to Install the IC -------------------------------- 63
12.1.4. How to Remove a Solder Bridge ---------------- 63

12.2. How to Replace the Shield Case--------------------- 64

12.2.1. Preparation-------------------------------------------- 64
12.2.2. Caution------------------------------------------------- 64
12.2.3. How to Remove the Shield Case---------------- 64
12.2.4. How to Install the Shield Case ------------------- 65

12.3. Terminal Guide of the ICs, Transistors, Diodes

and Electrolytic Capacitors ---------------------------- 66

12.3.1. Base Unit ---------------------------------------------- 66
12.3.2. Handset ------------------------------------------------ 66

13 Schematic Diagram -------------------------------------------- 67

13.1. For Schematic Diagram -------------------------------- 67

13.1.1. Base Unit (Base Unit (Main)) --------------------- 67
13.1.2. Handset (Handset) ---------------------------------- 67

13.2. Base Unit (Main) ----------------------------------------- 68

13.2.1. KX-TG6811RU --------------------------------------- 68
13.2.2. KX-TG6821RU --------------------------------------- 70

13.3. Base Unit (Operation) (KX-TG6821 only)---------- 72
13.4. Base Unit (TAM Counter) (KX-TG6821 only) ----- 72