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5.4
Failure diagnosis of the VCO section
Overview
The VCO circuit is mounted inside the BLS. BLS stands for "Board Level Shield".
This BLS has no lid and provides high shielding performance. Because BLS is difficult to solder, components inside the BLS can't be
soldered.
When there is a problem with the VCO circuit, the VCO can't be repaired.
If the VCO function doesn't work, use this flow chart to identify the problem.
The following is explained about failure diagnosis of VCO circuit inside a BLS<E101>.
BLS
BLS is shielding case
BLS for VCO area is integrated type and can not be removed
When the parts in the BLS is problematic, it is necessary to replace the printed circuit board by the Service Main unit in service.
Various ESN/default adjustment values are written on the service unit. Please refer to "5.6 Replacing Main Unit".
Prediction problem related to the VCO circuit
• PLL Unlock
<Radio state>
- Unlock beep
- VCO Assist voltage tuning is impossible
<The cause>
- VCO control voltage is abnormal
- VCO Assist voltage is abnormal
- VCO power supply is abnormal
- VCO signal output circuit is abnormal
VCO circuit inside a BLS<E101>
R46
R102
R106
0
22
10
DC amplifier (Assist)
C104
100p
C105
1u
IC101
IN+
V+
V-
IN-
oUT
OPA170AIDRLR
C103
33p
R108
R105
150k
E
D
G
IC102
IN+
VDD
VSS
R112
IN-
oUT
1k
BU7295HFV
C106
0.1u
1-66 (No.RA070<Rev.001>)
F
VCO H
L121
L131
C133
R127
R126
R128
100n
0
0
390
5p
VCO L
Q102
C153
EM6M2
L151
91n
7p
10M
CN101
50C
2SD2654/W/
C127
Q131
3p
C142
BFU660F
C134
D136
D134
1.3p
1.6p
1SV280FT
1SV280FT
R139
15
C171
3p
Q151
BFU660F
D156
D154
C156
C161
1SV280FT
1.9p
1.3p
1SV280FT
R155
8.2
Q113
L111
Q114
VT6M1
VCO circuit inside a BLS
[in a bold line square]
Q182
BFU660F
C138
CP101
22p
C145
0.5p
L137
39n
Q181
BFU660F
CP102
C166
C158
1.0p
22p
L157
100n
Q117
RE1E002SP
Q118
L113
BLS
E101
VT6M1
C
B
Q111
Q112
Q103
RE1E002SP
VT6M1
VT6M1
D103
C186
RN262CS
0.6p
A
R185
100
D104
C183
RN262CS
R198
0
0.75p
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