KX-TG2521RUT, KX-TGA251RUT — Panasonic Telephone Service Manual (repair manual)

Model
KX-TG2521RUT KX-TGA251RUT
Pages
77
Size
2.54 MB
Type
PDF
Document
Service Manual
Brand
Device
Telephone / DIGITAL CORDLESS ANSWERING SYSTEM
File
kx-tg2521rut-kx-tga251rut.pdf
Date

View Panasonic KX-TG2521RUT / KX-TGA251RUT Service Manual online

3
KX-TG2521RUT/KX-TGA251RUT
TABLE OF CONTENTS
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. 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. Signal Route -----------------------------------------------13
5 Location of Controls and Components ------------------15
6 Installation Instructions 
---------------------------------------15
7 Operating Instructions
-----------------------------------------15
7.1. For Service Hint-------------------------------------------15
8 Service Mode -----------------------------------------------------16
8.1. Engineering Mode ----------------------------------------16
8.2. Copying Phonebook Items when Repairing -------20
8.3. How to Clear User Setting------------------------------22
9 Troubleshooting Guide ----------------------------------------23
9.1. Troubleshooting Flowchart -----------------------------23
9.2. Troubleshooting by Symptom (Base Unit) ---------35
9.3. Troubleshooting by Symptom (Handset) -----------39
10 Disassembly and Assembly Instructions ---------------42
10.1. Disassembly Instructions -------------------------------42
10.2. How to Replace the Handset LCD -------------------44
11 Measurements and Adjustments---------------------------45
11.1. Equipment Required -------------------------------------45
11.2. The Setting Method of JIG (Base Unit) -------------45
11.3. Adjustment Standard (Base Unit)---------------------47
11.4. The Setting Method of JIG (Handset) ---------------48
11.5. Adjustment Standard (Handset) ----------------------50
11.6. Things to Do after Replacing IC or X'tal ------------51
11.7. RF Specification-------------------------------------------53
11.8. How to Check the Handset Speaker or
Receiver ----------------------------------------------------54
11.9. Frequency Table (MHz) ---------------------------------54
12 Miscellaneous ----------------------------------------------------55
12.1. How to Replace the Flat Package IC ----------------55
12.2. How to Replace the Shield Case ---------------------57
12.3. Terminal Guide of the ICs, Transistors, Diodes
and Electrolytic Capacitors-----------------------------59
13 Schematic Diagram ---------------------------------------------60
13.1. For Schematic Diagram---------------------------------60
13.2. Schematic Diagram (Base Unit) ----------------------62
13.3. Schematic Diagram (Handset) ------------------------64
14 Printed Circuit Board-------------------------------------------67
14.1. Circuit Board (Base Unit_Main)-----------------------67
14.2. Circuit Board (Handset) ---------------------------------69
15 Exploded View and Replacement Parts List -----------71
15.1. Cabinet and Electrical Parts (Base Unit) -----------71
15.2. Cabinet and Electrical Parts (Handset) -------------72
15.3. Accessories ------------------------------------------------73
15.4. Replacement Part List-----------------------------------74
4
KX-TG2521RUT/KX-TGA251RUT
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
prevent 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.
2 Warning
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 manufacture’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
contains 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 
temperature 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).
5
KX-TG2521RUT/KX-TGA251RUT
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 manufacturer’s
specific instructions for the melting points of their products and any precautions for using their product with other materials. 
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.
6
KX-TG2521RUT/KX-TGA251RUT
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
7
KX-TG2521RUT/KX-TGA251RUT
4 Technical Descriptions
4.1.
Block Diagram (Base Unit)
Analog
Front
End
T
o TEL_LINE
Bridge
Rect
 D3D3
Hook Switch
Q3,Q4,Q5
Audio
Bell/Caller ID
Interface
CPU
18
16
23
20
21
19
24
BELL
HOOK
Off-Hook Line Voltage
25
A/D
D/A
ADPCM
Codec Filter
DSP
Speech Encoding
Speech Decoding
BMC
Burst Encoding
Burst Decoding
RF
PLL
5
3
77
75
9
10
EEPROM
SCL
SDA
57
58
44
To AC Adaptor
Limit
Resistor
Charge
Detector
CHARGE
CONTACT
(Optional)
IC2
Q9
Q8
2.4V
Reg.
1.8V
Reg.
3.0 V
2.4 V
1.8 V
BBIC
IC401
IC7
KX-TG2521 BLOCK DIAGRAM 
(BASE UNIT)
MOD/DEMOD
Charge
Pump
43
2.5V
X
T
A
L
X
1
X1
1
0.3
68
M
H
z
IC801
R
X
n
R
X
p
T
X
p
T
X
n
P
on
P
S
E
L
V
D
D
-P
A
D
R
V
4
3
6
7
T
X
on
R
X
on
D801
6
72
AN
T1
AN
T2
9
8
AN
T1
ANT2
R
F
 P
A
ANT1
AN
T2
78
73
74
80
L
1
L
2
D
C
P
D
C
M
2
FLASH MEMORY
IC421
42
3.0V
54 
55
56 
53
TA
M-C
Sn
SP
I-DI
SP
I-DO
SP
ICL
K
IC3

Download Panasonic KX-TG2521RUT / KX-TGA251RUT Service Manual (Repair Manual)

Here you can view online or download Panasonic KX-TG2521RUT / KX-TGA251RUT Service Manual in pdf. This Service Manual can help you recover, restore, fix, disassemble and repair Panasonic KX-TG2521RUT / KX-TGA251RUT Telephone. Information contained in Panasonic KX-TG2521RUT / KX-TGA251RUT service manual (repair manual) typically includes:

  • Disassembly, troubleshooting, programming, maintenance, remote, adjustment, installation and setup instructions.
  • Schematics, wiring and block diagrams.
  • Printed wiring boards (PWB) and printed circuit boards (PCB).
  • Parts list (bill of materials).