KX-NT553RU-B, KX-NT556RU-B - Panasonic Telephone Service Manual (repair manual). Page 2

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1 Safety Precautions -----------------------------------------------3

1.1. For Service Technicians  ---------------------------------3

2 Warning --------------------------------------------------------------4

2.1. About Lead Free Solder (PbF: Pb free) --------------4

2.1.1. Suggested PbF Solder -------------------------------4

2.2. Discarding of P. C. Board --------------------------------4

3 Specifications ------------------------------------------------------5
4 Technical Descriptions------------------------------------------6

4.1. Block Diagram ----------------------------------------------6
4.2. Circuit Operations ------------------------------------------7

4.2.1. LCD Circuit (Main LCD/Selflabeling LCD) ------7
4.2.2. Reset Circuit --------------------------------------------8
4.2.3. Ethernet Circuit ----------------------------------------9
4.2.4. Analog Circuit ------------------------------------------9
4.2.5. ASIC (IC205) ----------------------------------------- 11
4.2.6. Key Circuit--------------------------------------------- 12
4.2.7. LED Circuit -------------------------------------------- 14
4.2.8. EHS Circuit-------------------------------------------- 15
4.2.9. Power Supply Circuit ------------------------------- 16

5 Location of Controls and Components------------------ 17

5.1. Name and Locations ------------------------------------ 17

6 Installation Instructions--------------------------------------- 18

6.1. Connections ----------------------------------------------- 18

7 Test Mode ---------------------------------------------------------- 20

7.1. Loopback Test Mode ------------------------------------ 20

7.1.1. Preparation-------------------------------------------- 20
7.1.2. Communication Test -------------------------------- 20
7.1.3. Quit Test Mode for communication test  ------- 20

7.2. KEYs and LEDs Test mode---------------------------- 21

7.2.1. Preparation-------------------------------------------- 21
7.2.2. KEYs and LEDs Test ------------------------------- 21
7.2.3. Quit KEYs and LEDs Test mode----------------- 21

8 Service Mode ----------------------------------------------------- 22

8.1. Factory Setting-------------------------------------------- 22

8.1.1. How to Clear User Setting ------------------------ 22

8.2. How to Change MAC Address Label---------------- 22

8.2.1. Replacing Main P.C.B. ----------------------------- 22
8.2.2. Attaching MAC Address Label ------------------- 23

9 Troubleshooting Guide---------------------------------------- 24

9.1. No Operation ---------------------------------------------- 24

9.1.1. Power ON Error -------------------------------------- 24
9.1.2. Power Supply : AC adaptor ----------------------- 24
9.1.3. Power Supply : PoE -------------------------------- 25

9.2. Main LCD Does Not Operate ------------------------- 32
9.3. ASIC Does Not Work------------------------------------ 33

9.3.1. ASIC Data Error ------------------------------------- 33

9.4. Handset Does Not work -------------------------------- 34

9.4.1. Receive ------------------------------------------------ 34
9.4.2. Send ---------------------------------------------------- 34

9.5. Headset Does Not work -------------------------------- 35

9.5.1. Receive ------------------------------------------------ 35
9.5.2. Send ---------------------------------------------------- 35

9.6. Speaker-Phone Does Not Work ---------------------- 36

9.6.1. Receive ------------------------------------------------ 36
9.6.2. Send ---------------------------------------------------- 36

9.7. Ethernet Does Not work -------------------------------- 37

9.7.1. PHY Data Error -------------------------------------- 37
9.7.2. LAN port ----------------------------------------------- 38

9.7.3. PC port ------------------------------------------------ 38

9.8. LED Does Not Light ------------------------------------- 39
9.9. EHS Does Not Work ------------------------------------ 40

9.9.1. Plantronics EHS Does Not Work---------------- 40
9.9.2. Jabra EHS Does Not Work ----------------------- 41

10 Disassembly and Assembly Instructions -------------- 42

10.1. Remove Main Board and Ope Board --------------- 42
10.2. Remove and Assembly for LCD  -------------------- 43
10.3. Assembly for Lead wire -------------------------------- 44

11 Maintenance------------------------------------------------------ 45

11.1. Terminal Guide of the ICs Transistors and

Diodes ------------------------------------------------------ 45

11.1.1. Main Board ------------------------------------------- 45
11.1.2. Operation Board------------------------------------- 45

11.2. How To Replace a Flat Package IC ----------------- 46

11.2.1. Preparation ------------------------------------------- 46
11.2.2. Removal Procedure -------------------------------- 46
11.2.3. Procedure--------------------------------------------- 46
11.2.4. Removing Solder From Between Pins--------- 46

11.3. Memo ------------------------------------------------------- 47

12 Schematic Diagram -------------------------------------------- 48

12.1. Main No.1-------------------------------------------------- 48
12.2. Main No.2-------------------------------------------------- 52
12.3. Main No.3-------------------------------------------------- 56
12.4. Main No.4-------------------------------------------------- 60
12.5. Ope---------------------------------------------------------- 64
12.6. Waveform -------------------------------------------------- 68

12.6.1. No.(1)-(5)---------------------------------------------- 68
12.6.2.  No.(6)-(10) ------------------------------------------- 69
12.6.3. No.(11)-(15(1)) --------------------------------------- 70
12.6.4. No.(15(2))-(19(1)) ----------------------------------- 71
12.6.5. No.(19(2))-(23)--------------------------------------- 72
12.6.6. No.(23(2)) --------------------------------------------- 73

13 Printed Circuit Board------------------------------------------ 74

13.1. Main Board ------------------------------------------------ 74

13.1.1. Component View ------------------------------------ 74
13.1.2. Bottom View ------------------------------------------ 75

13.2. Operation Board ----------------------------------------- 76

13.2.1. Component View ------------------------------------ 76

13.3. DSS Relay Board ---------------------------------------- 77
13.4. MIC Board ------------------------------------------------- 77
13.5. LCD Back Light Board---------------------------------- 77

14 Appendix Information of Schematic Diagram -------- 78
15 Exploded View and Replacement Parts List----------- 79

15.1. IC Data ----------------------------------------------------- 79

15.1.1. IC502--------------------------------------------------- 79
15.1.2. IC301--------------------------------------------------- 85

15.2. Cabinet and Electric Parts----------------------------- 88
15.3. Accessories and Packing Materials ----------------- 89
15.4. Replacement Parts List -------------------------------- 90

15.4.1. Cabinet and Electrical Parts---------------------- 90
15.4.2. Accessories and Packing Materials ------------ 91
15.4.3. Main Board Parts ----------------------------------- 91
15.4.4. Ope Board Parts ------------------------------------ 95