KX-TG7225RUJ, KX-TG7225RUM, KX-TG7225RUS, KX-TG7225RUT, KX-TG7226RUS, KX-TG7226RUT, KX-TGA721RUJ, KX-TGA721RUM, KX-TGA721RUS, KX-TGA721RUT - Panasonic Telephone Service Manual (repair manual). Page 3

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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

3 Specifications ----------------------------------------------------- 6
4 Technical Descriptions ----------------------------------------- 7

4.1. Block Diagram (Base Unit) ------------------------------ 7
4.2. Circuit Operation (Base Unit) --------------------------- 8
4.3. Block Diagram (Handset)-------------------------------11
4.4. Circuit Operation (Handset)----------------------------12
4.5. Circuit Operation (Charger Unit) ----------------------13
4.6. Signal Route -----------------------------------------------14

5 Location of Controls and Components ------------------16

5.1. Controls -----------------------------------------------------16

6 Installation Instructions ---------------------------------------16

6.1. Connections------------------------------------------------16
6.2. Battery-------------------------------------------------------17

7 Operation Instructions-----------------------------------------18

7.1. Base Unit Settings----------------------------------------18
7.2. Handset Settings -----------------------------------------19
7.3. Registering a Handset to the Base Unit ------------20
7.4. Copying Phonebook Entries ---------------------------21
7.5. Dialling Mode (Tone/Pulse) ----------------------------21
7.6. Error Message---------------------------------------------21
7.7. Troubleshooting-------------------------------------------22
7.8. For Service Hint-------------------------------------------24

8 Service Mode -----------------------------------------------------25

8.1. Engineering Mode ----------------------------------------25
8.2. Copying Phonebook Items when Repairing -------29
8.3. How to Clear User Setting------------------------------31

9 Troubleshooting Guide ----------------------------------------32

9.1. Troubleshooting Flowchart -----------------------------32
9.2. Troubleshooting by Symptom (Base Unit and

Charger Unit) ----------------------------------------------44

9.3. Troubleshooting by Symptom (Handset) -----------47
9.4. How to Replace the Flat Package IC----------------50
9.5. How to Replace the LLP (Leadless Leadframe

Package) IC------------------------------------------------52

10 Disassembly and Assembly Instructions ---------------54

10.1. Disassembly Instructions -------------------------------54
10.2. How to Replace the Handset LCD -------------------58

11 Measurements and Adjustments---------------------------59

11.1. The Setting Method of JIG (Base Unit) -------------59
11.2. Adjustment Standard (Base Unit)---------------------61
11.3. Adjustment Standard (Charger Unit)-----------------62
11.4. The Setting Method of JIG (Handset) ---------------63
11.5. Adjustment Standard (Handset) ----------------------65
11.6. Things to Do after Replacing IC or X'tal ------------66
11.7. RF Specification-------------------------------------------67
11.8. How to Check the Handset Speaker or

Receiver ----------------------------------------------------68

11.9. Frequency Table (MHz) ---------------------------------68

12 Schematic Diagram ---------------------------------------------69

12.1. For Schematic Diagram---------------------------------69
12.2. Schematic Diagram (Base Unit) ----------------------70
12.3. Schematic Diagram (Base Unit_Operation) -------72
12.4. Schematic Diagram (Handset) ------------------------74

12.5. Schematic Diagram (Charger Unit)------------------ 76

13 Printed Circuit Board ------------------------------------------ 77

13.1. Circuit Board (Base Unit_MAIN) --------------------- 77
13.2. Circuit Board (Base Unit_Operation)---------------- 79
13.3. Circuit Board (Handset) -------------------------------- 81
13.4. Circuit Board (Charger Unit)--------------------------- 83

14 Appendix Information of Schematic Diagram --------- 84

14.1. CPU Data (Base Unit) ---------------------------------- 84
14.2. CPU Data (Handset) ------------------------------------ 86
14.3. Terminal Guide of the ICs, Transistors and

Diodes ------------------------------------------------------ 88

15 Exploded View and Replacement Parts List ----------- 89

15.1. Cabinet and Electrical Parts (Base Unit) ----------- 89
15.2. Cabinet and Electrical Parts (Handset)------------- 90
15.3. Cabinet and Electrical Parts (Charger Unit) ------- 91
15.4. Accessories and Packing Materials ----------------- 92
15.5. Replacement Part List ---------------------------------- 95