Panasonic KX-NT305X Service Manual ▷ View online
9
KX-NT305X / KX-NT305X-B
7 Miscellaneous
7.1.
Terminal Guide of ICs, Transistors and Diodes
10
KX-NT305X / KX-NT305X-B
7.2.
How To Replace a Flat Package IC
Even if you do not have the special tools (for example, a spot heater) to remove the Flat IC, with some solder (large amount), a sol-
dering iron and a cutter knife, you can easily remove the ICs that have more than 100 pins.
dering iron and a cutter knife, you can easily remove the ICs that have more than 100 pins.
7.2.1.
Preparation
• PbF (: Pb free) Solder
• Soldering Iron
• Soldering Iron
Tip Temperature of 700
°F ± 20°F (370°C ± 10°C)
Note: We recommend a 30 to 40 Watt soldering iron. An
expert may be able to use a 60 to 80 Watt iron where some-
one with less experience could overheat and damage the
PCB foil.
expert may be able to use a 60 to 80 Watt iron where some-
one with less experience could overheat and damage the
PCB foil.
• Flux
Recommended Flux: Specific Gravity
→ 0.82.
Type
→ RMA (lower residue, non-cleaning type)
Note: See About Lead Free Solder (PbF: Pb free) (P.3).
7.2.2.
Removal Procedure
1. Put plenty of solder on the IC pins so that the pins can be
completely covered.
Note:
Note:
If the IC pins are not soldered enough, you may give
pressure to the P.C. board when cutting the pins with
a cutter.
pressure to the P.C. board when cutting the pins with
a cutter.
2. Make a few cuts into the joint (between the IC and its
pins) first and then cut off the pins thoroughly.
3. While the solder melts, remove it together with the IC
pins.
When you attach a new IC to the board, remove all solder
left on the land with some tools like a soldering wire. If some
solder is left at the joint on the board, the new IC will not be
attached properly.
left on the land with some tools like a soldering wire. If some
solder is left at the joint on the board, the new IC will not be
attached properly.
7.2.3.
Procedure
1. Tack the flat pack IC to the PCB by temporarily soldering
two diagonally opposite pins in the correct positions on
the PCB.
the PCB.
Be certain each pin is located over the correct pad on the PCB.
2. Apply flux to all of the pins on the IC.
3. Being careful to not unsolder the tack points, slide the sol-
dering iron along the tips of the pins while feeding enough
solder to the tip so that it flows under the pins as they are
heated.
solder to the tip so that it flows under the pins as they are
heated.
7.2.4.
Removing Solder From Between
Pins
Pins
1. Add a small amount of solder to the bridged pins.
2. With a hot iron, use a sweeping motion along the flat part
2. With a hot iron, use a sweeping motion along the flat part
of the pin to draw the solder from between the adjacent
pads.
pads.
11
KX-NT305X / KX-NT305X-B
Memo
12
KX-NT305X / KX-NT305X-B
8 Schematic Diagram
8.1.
Block Diagram
D3.3V
150
R17
150
R15
150
R23
150
R19
150
R21
Q7
1
2
3
4
5
Q8
1
2
3
4
5
Q10
1
2
3
4
5
Q6
1
2
3
4
5
Q9
1
2
3
4
5
LED30
CO30
1
2
3
4
LED25
CO25
1
2
3
4
LED10
CO10
1
2
3
4
LED20
CO20
1
2
3
4
LED5
CO5
1
2
3
4
LED29
CO29
1
2
3
4
LED9
CO9
1
2
3
4
LED4
CO4
1
2
3
4
LED14
CO14
1
2
3
4
LED24
CO24
1
2
3
4
LED19
CO19
1
2
3
4
LED28
CO28
1
2
3
4
LED8
CO8
1
2
3
4
LED3
CO3
1
2
3
4
LED13
CO13
1
2
3
4
LED23
CO23
1
2
3
4
LED18
CO18
1
2
3
4
LED27
CO27
1
2
3
4
LED7
CO7
1
2
3
4
LED2
CO2
1
2
3
4
LED12
CO12
1
2
3
4
LED17
CO17
1
2
3
4
LED26
CO26
1
2
3
4
LED6
CO6
1
2
3
4
LED1
CO1
1
2
3
4
LED11
CO11
1
2
3
4
LED21
CO21
1
2
3
4
LED16
CO16
1
2
3
4
LED15
CO15
1
2
3
4
LED22
CO22
1
2
3
4
SW13
CO13
SW3
CO3
SW26
CO26
SW1
CO1
SW2
CO2
SW23
CO23
SW24
CO24
SW22
CO22
SW21
CO21
SW12
CO12
SW25
CO25
SW11
CO11
SW6
CO6
SW18
CO18
SW19
CO19
SW28
CO28
SW27
CO27
SW9
CO9
SW30
CO30
SW17
CO17
SW10
CO10
SW4
CO4
SW14
CO14
SW29
CO29
SW15
CO15
SW7
CO7
SW16
CO16
SW
5
CO5
SW20
CO20
SW8
CO8
43
R20
43
R16
43
R22
43
R24
43
R18
L[10]
L[9]
L[8]
L[7]
L[6]
L[5]
L[4]
L[3]
L[2]
L[1]
K[5]
K[4]
K[3]
K[2]
K[1]
R
G
R
R
R
G
G
G
R
G
R
G
R
G
R
R
G
R
G
R
G
G
G
R
R
R
G
R
G
R
G
R
G
G
G
R
R
G
R
G
R
G
G
G
R
R
R
G
R
G
R
G
R
G
G
G
R
R
R
G
(1)
(2)
(3)
(8)
(4)
(5)
(6)
(7)
KX-NT305X / KX-NT305X-B : MAIN BOARD (1/3)
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