Panasonic KX-T7740X (serv.man2) Service Manual ▷ View online
1 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.
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).
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 although, with some precautions, standard Pb solder can also be used.
work we suggest using the same type of solder although, with some precautions, standard Pb solder can also be used.
Caution
•
•
•
• PbF solder has a melting point that is 50° ~ 70° F, (30° ~ 40°C) higher than Pb solder. Please use a soldering iron with
temperature control and adjust it to 700° ± 20° F, (370° ± 10°C). In case of using high temperature soldering iron, please
be careful not to heat too long.
be careful not to heat too long.
•
•
•
• PbF solder will tend to splash if it is heated much higher than its melting point, approximately 1100°F, (600°C).
•
•
•
• If you must use Pb solder on a PCB manufactured using PbF solder, remove as much of the original PbF solder as possible
and be sure that any remaining is melted prior to applying the Pb solder.
•
•
•
• When applying PbF solder to double layered boards, please check the component side for excess which may flow onto the
opposite side (See figure, below).
1.1. 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 gauges are recommended for service of this product: 0.3mm, 0.6mm and 1.0mm.
(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 gauges are recommended for service of this product: 0.3mm, 0.6mm and 1.0mm.
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KX-T7740X-B
1.2. HOW TO RECOGNIZE THAT Pb FREE SOLDER IS USED
PbF is stamped to show that Pb free solder is used. (See the figure below.)
E4
B4
A4
A1
B1
A2
B2
B3
A3
A6
D5V
GND
T1
IC2
A7
IC3
C5
10
6
C1
R1
R2
D3
R15
5
1
1
7
C2
R8
R3
R4
8
14
C7
Q1
Q2
R6
D2
R7
C3
R5
A5
E5
B8
R
B6
B9
E1
E2
B7
B10
E3
L
T
H
D1
B5
Q11
IC1
32
33
48
49
64
C11
C9
R13
R14
R28
IC4
RA1
C12
C10
1
16
17
R21
R22
C13
C8
R10 R9
R11
R12
X1
R24
R23
R25
Q14 R27
JK1
R26
Q12
Q13
C4
C6
Q15
Q16
Q17
PSUP1383Z
A
KX-T7740X-B MAIN BOARD
COMPONENT VIEW
Marked PbF (PbF is marked around here)
PbF
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KX-T7740X-B
2 FOR SERVICE TECHNICIANS
ICs and LSIs are vulnerable to static electricity.
When repairing, the following precautions will help prevent recurring malfunctions.
1. Cover the plastic parts boxes with aluminum foil.
2. Ground the soldering irons.
3. Use a conductive mat on the worktable.
4. Do not touch IC or LSI pins with bare fingers.
When repairing, the following precautions will help prevent recurring malfunctions.
1. Cover the plastic parts boxes with aluminum foil.
2. Ground the soldering irons.
3. Use a conductive mat on the worktable.
4. Do not touch IC or LSI pins with bare fingers.
3 SPECIFICATIONS
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KX-T7740X-B
4 LOCATION OF CONTROLS
5 CONNECTION
Caution:
Ensure the cord is inserted in the groove to prevent damage to the connector.
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KX-T7740X-B
