Panasonic KX-TCA285RU Service Manual ▷ View online
49
KX-TCA285RU
12.2. 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.
12.2.1.
Preparation
• PbF (: Pb free) Solder
• Soldering Iron
• Soldering Iron
Tip Temperature of 700
F ± 20F (370C ± 10C)
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.4).
12.2.2.
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.
12.2.3.
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.
12.2.4.
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.
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KX-TCA285RU
12.3. How to Replace the LLP (Leadless Leadframe Package) IC
12.3.1.
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 someone with less
experience could overheat and damage the PCB foil.
We recommend a 30 to 40 Watt soldering iron. An expert may be able to use a 60 to 80 Watt iron where someone with less
experience could overheat and damage the PCB foil.
• Hot Air Desoldering Tool
Temperature: 608
F ± 68 F (320 C ± 20 C)
12.3.2.
Caution
• To replace the IC efficiently, choose the right sized nozzle of the hot air desoldering tool that matches the IC package.
• Be careful about the temperature of the hot air desoldering tool not to damage the PCB and/or IC.
• Be careful about the temperature of the hot air desoldering tool not to damage the PCB and/or IC.
12.3.3.
How to Remove the IC
1. Heat the IC with a hot air desoldering tool through the
P.C.Board.
2. Pick up the IC with tweezers, etc. when the solder is
melted completely.
Note:
Note:
• Be careful not to touch the peripheral parts with twee-
zers, etc. They are unstable.
When it is hard to melt the solder completely, heat it with
a hot air desoldering tool through the IC besides through
the P.C.Board.
a hot air desoldering tool through the IC besides through
the P.C.Board.
3. After removing the IC, clean the P.C.Board of residual sol-
der.
12.3.4.
How to Install the IC
1. Place the solder a little on the land where the radiation
GND pad on IC bottom is to be attached.
2. Place the solder a little on the land where IC pins are to
be attached, then place the IC.
Note:
Note:
• When placing the IC, the positioning should be done very
carefully.
3. Heat the IC with a hot air desoldering tool through the
P.C.Board until the solder on IC bottom is melted.
Note:
Note:
• Be sure to place it precisely, controlling the air volume of
the hot air desoldering tool.
4. After soldering, confirm there are no short and open cir-
cuits with visual inspection.
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KX-TCA285RU
12.3.5.
How to Remove a Solder Bridge
When a Solder Bridge is found after soldering the bottom of the IC, remove it with a soldering iron.
52
KX-TCA285RU
13 Schematic Diagram
13.1. Handset
KX-TCA285
58 MAIN BOARD No.1 1/2
(1)
(2)
(3)
(4)
(3)
(4)
(5)
(6)
(8)
(8)
(7)
(9)
(10)
(11)
(12)
(14)
(14)
(15)
(16)
(16)
(17)
(13)
Charge Current
3.4 - 4.2V
3.0V
5.0V
3.0V
1.775V
3.0V
(When Bluetooth on)
5.0V
(When LCD backligth on)
C
E
B
A
D
F
3
4
2
1
5
CHG_CUR
CP_ON
ON/OFF
KBIO_7
ON/OFF
KBIO_7
VIB_CTRL
BT_ON
CHG_DET
TH
TH
COUNT
COUNT
BT_ON
CHG_CUR
CP_ON
BATTERY
GND
PNLB2026ZA-EC
PCB
RE1
RE1
GND
C302
C301
0.1u
0.1u
GND
NC
C307
GNDA
GND
GNDA
VBAT_3.0V
LNA_INN
ANT2
ANT1
RX_SW
TX_SW
BAL_OUT1
RSTN
C10
0.1u
C12
0.1u
C11
N
C
GND
BATTERY
VBAT_MON
GNDA
NC
C306
Li_BATT+
Li_BATT-
VBG
BATT
GND
GND
C305
0.039u (1608)
C202
L2
120
C206
GND
CN500
1
2
2
BAL_OUT2
5.0V
IF_BAT_OK
IF_CDC_DAT_DA
IF_CDC_DAT_AD
IF_CDC_DIR
IF_CLK_IF
IF_CLK_PLL
IF_DATA_AD
IF_DATA_DA
IF_EN_AD
IF_EN_DA
IF_INT_ANA
IF_NARES
IF_NPORST
IF_T_DATA
IF_RX1
IF_MLSE
VDDC
VDDC
0.1u
CP_ON
F201
2.5A
C4
NC
VCCA
CHG+
CHG-
C23
ON/OFF
KBIO_7
GND
LNA_INP
VCC_PA
R543
NC
R542
1.8k
R7
100k
R300
3.3k
R6
10
C207
NC
D540
CHG_State
VBAT_3.0V
BT3.0V
BATTERY
BT_ON
GND
GND
Li_TH
BATTERY
IC205
1
VIN
2
VSS
3
ON/OFF
5
VOUT
4
NC
GND
C6
(1608)
10u
C14
(1608)
10u
C19 10u
(1608)
(1608)
BATTERY
C5
1u
C15
1u
C226
1u
C217
R210
100k
GND
ATSTN
ATSTP
L200
L201
C211
33p
GND
GND
CHG(+)
CHG(-)
R8
1M
R9
330k
DOUT3.0V
BT3.0V
C218
1u
GND
R217
470k
GND
GND
R220 100k
IC203
1 VCC
2 ROSC
3 LED
4 GND
5 VDD
6
TH
7
TMRCNT
8
RICHG
9
VSENSE
10
BAT
11
FIN
C213
1u
GND
R201
0.1
39p
R540
R541
33
33
Q540
RA300
3.3k
1 23
4
C203
5.0V
R219
F270k
R218
R3
C9
1u
C2
(1608)
10u
R204
NC
GND
C201
4.7u (1608)
(3216)
6.3
100
GND
VBAT_3.0V
GND
DOUT3.0V
R207
NC
R208
33k
GND
R209
18k
C1
1u
C204
4.7u (1608)
C216
0.1u
C215
1u
R216
3.3k
IC201
1 VOUT
2 GND
2 GND
4
C-
5
VIN
3 *SHDN
6
C+
IC200
NC
1 OUT
2 VDD 3
2 VDD 3
NC
4
VSS
R206
VBAT_3.0V
GND
GND
GND
R203
NC
C223
100u
R205
F30k
F60.4k
C3
3.0V
R402
470k
GND
D203
NC
IC202
1
VOUT1
2
VOUT2
3
ADJ
4 GND1
5 CE
6 VDD
7
GND2
ZA1
2
3
4
1
L22
L1 22u
C210
NC
GND
C13
10u
IC1
1
DOUBCAPP2
2
DOUBCAPN1
18
SPOUTP
3
DOUBCAPP1
4
DOUT3V0
5
DOUT4V5
6
DOUT2V5/DCIN0/LIN0
7
LEDSINK2/DCIN1
8
DCIN2
19
VCCPA
20
SPOUTN
21
HSSPOUTP
22
LOUT
23
PWM0
24
DCINS
25
XOUT
38
TEST
39
RX_SW
40
LNA_INN
69
GND
9
DCIN3/LIN1
10
LEDSINK1/PWM1
11
VREF
12
VCCA
13
MIN
14
MIP
15
HSMIN
16
HSMIP
26
XIN
27
VDD_APU
28
VBAT_APU
29
VDD_IF
30
VCC_FE_IF
31
VCC_PA
32
BAL_OUT2
33
BAL_OUT1
41
LNA_INP
42
ATST_N
43
ATST_P/EXT_LNA
44
RSTN
45
VCC_VCO
46
ON_OFF
47
ON_OFF_OUT
48
IF_T_DATA
49
IF_MLSE
50
IF_RX1
51
IF_NPORST
53 IF_INT_ANA
54 IF_EN_DA
55 IF_EN_AD
56 IF_DATA_DA
57 IF_DATA_AD
58 IF_CLK_PLL
59 IF_CLK_IF
60 IF_CDC_DIR
61 IF_CDC_DAT_DA
62 IF_CDC_DAT_AD
63 IF_BAT_OK
64 VDD_ADIF
65 VDDCORE
66 COREOUT
67 VBAT
68 DOUBCAPN2
36
GND_RF
37
ANT2
17
MPWR
34
TX_SW
35
ANT1
52 IF_NARES
C40
1.5p
To Charge
Terminal
To Battery
Li-Ion
TO RF BLOCK
VIB
TO DPU
H:ON
L:OFF
H:ON
L:OFF
39p
C21 2.2u
(1608)
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