Kenwood TH-D72A Service Manual page 97

Transmitter Section
8mVrms 24mVrms
IC712
2 1 3
MIC MIC
CN715
AMP
2
3
IC714
7
2/2
6
MIC
AGC
Receiver Section
Center Frequency
–60dBm –72.5dBm –52.5dBm
D215,216
D219,221
ANT
ANT BPF
SW
Q11 Q7
A Band VHF Receiver circuit
–71dBm –56dBm
BPF
Q13 Q8
B Band VHF Receiver circuit
–68dBm –51dBm
D217
D220,222
ANT
BPF
SW
Q10 Q6
A Band UHF Receiver circuit
–67dBm –53.5dBm
BPF
Q9 Q5
B Band UHF Receiver circuit
AF (1kHz)
0.84Vp-p: 1200bps
0.5Vp-p: 9600bps
3.2Vp-p: 1200bps 2.3Vp-p: 1200bps 199mVrms: VHF
780mVrms 570mVrms 127mVrms: UHF
IC716 7 2 3
IDC &
IC721
7
SPL
E VR
filter
5 4
1.4Vp-p: 9600bps 1.64Vp-p: 1200bps
0.98Vp-p: 9600bps
400mVrms: VHF
3.3Vp-p: 1200bps 135mVrms: UHF
2.4Vp-p: 1200bps
29
IC735
IC728
SW
TNC
2 1 35
ASIC
2.8Vp-p: 9600bps 3.3Vp-p: 9600bps
49.95MHz 450kHz
–46dBm –39dBm: VHF
–42dBm: UHF
XF351
IC353
BPF MCF 16
FM IC
Q2
CF
1st Local
45.05MHz 455kHz
–48dBm: VHF
–51.5dBm –45.5dBm: UHF
XF352
IC354
BPF MCF 16
FM IC
Q4
CF
1st Local
–50dBm
BPF
Q3
1st Local
Note1: The RF levels for each point, are at 1000pF with a spectrum analyzer through a capacitor.
–53dBm
When the –60dBm standard signal generator by a no modulation from ANT connecter.
Note2: The AF levels were measured with an oscilloscope when the –60dBm standard signal generator signal modulated by a 1kHz modulation frequency and
a 3kHz deviation was input and the AF output was adjusted to 0.63V/8Ω by the AF VR.
BPF
Note3: This is the value measured with an oscilloscope at each point, where the data level inputs a –60dBm SSG signal to the VHF zone frequency using the following settings.
Q1
1200bps: 1kHz MOD, 3kHz DEV.
9600bps: 1kHz MOD, 2kHz DEV.
1st Local
–7.8dBm: VHF –10.3dBm: VHF
–9.8dBm: UHF –8.5dBm: UHF
C594
C223
R532
VCO
B
C574
Q201
TCXO
(B)
X511
Note1: This is the value measured while removed from the chassis. Use a short transmission burst.
In the worst case scenario, some parts will be damaged. During this test, some parts will reach high temperature.
Note2: For the 1kHz MOD to become 8mVrms, set the MIC input terminal to AG.
Note3: Set the transmission output to Low.
Note4: Connect a 50Ω terminal load or power meter to the ANT terminal.
Note5: When measuring data levels of 1200/9600bps, transmit the BEACON at 1200bps and 9600bps.
CONT RF Refer to the instruction manual for the settings.
Note6: The RF levels for each point, other than for the ANT terminal, are measured at 1000pF with a spectrum analyzer
through a capacitor.
Note7: Measure the AF level and Data level values with an oscilloscope.
185mVrms 175mVrms 55mVrms
A Band
9
AF 14 15
IC721
E VR
17 16
AF (1kHz)
170mVrms 200mVrms
9
8
175mVrms
6 7
IC722
IC352
B Band 7 1 200mVrms
Multi
9
AF
SW
0.5Vp-p: 1200bps
0.3Vp-p: 9600bps
7
IC720
1 13
Multi
6
SW
RF CONT
Center Frequency
+4.3dBm: VHF +9.5dBm: VHF
+7.8dBm: UHF +9.3dBm: UHF
LPF
C248 C260
4 1
ATT
IC202
Q214
HPF
AF (1kHz)
115mVrms 59mVrms 58mVrms
VOL
CN701
Q717 Q715 Q718 Q711
De-emp AMP
TONE A 128
IC737
Main
MCU
TONE B 126
3.2Vp-p 3.3Vp-p 2.4Vp-p
Q728
14 1200pbs
2 1 2
IC733
IC722
IC732
Buff
6 7 5
9600pbs
Q729
3.3Vp-p 2.7Vp-p
0.5W
LPF
ANT
Q215 LPF HPF
10mVrms 840mVrms 0.63Vrms
2 6
(SP)
8Ω
CN715
IC734
Q703
AF AMP
1 16
IC728
TNC
ASIC
7 14