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Troubleshooting
68P02963C70-O
3 - 23
Synthesizer Troubleshooting
Use this test on a unit with the following symptom: no Tx or Rx
Using a 50-ohm probe on the
spectrum analyzer,check the LO
output at the buffer output at
R927 and R944.
Is the frequency
at 503.65MHz?
Is the buffer
output between
-5 and -3dBm ?
The unit tested successfully
check the VCO
output at R937 ,Is
the freq 529.65MHz
?
Test the VCO control
voltage at R917.The typical
range is 0.5 to 4.5 V.
Check for opens,shorts,or
missing components in the
buffer circuits.
Also check for 2.3 Vdc on
L907.
Is the control
voltage railed to
<0.5V or >4.5V
Possible prescaler feedback
problem:
1.check solderin of
C933,C915.
2.Probe to determine if LO
is reaching the prescaler
input.
NO
YES
YES
NO
YES
Note:This is
the abnormal
condition.
No
A
NO
YES
TetraCom Commands:
MAIN_VCO ON
WPIC 3 1 c0 NOW
WPIC 2 4 17 NOW
WPIC 2 5 F4 NOW
WPIC 2 6 9e NOW
WPIC 2 7 79 NOW
WPIC 0 5 30 NOW
WPIC 0 8 0 NOW
Содержание MTH500
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Страница 14: ...Foreword xiv 68P02963C70 O THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 18: ...Overview 1 4 68P02963C70 O THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 50: ...Theory of Operation 2 32 68P02963C70 O THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 76: ...Troubleshooting 3 26 68P02963C70 O Offset VCO Test ...
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Страница 82: ...Programming the Radio 4 4 68P02963C70 O This page left blank intentionally ...
Страница 100: ...Maintenance 5 18 68P02963C70 O Figure 23 Exploded View 1 2 3 4 5 7 6 X6 8 ...
Страница 101: ...Maintenance 68P02963C70 O 5 19 Figure 24 Exploded View of Chassis Assembly 9 12 13 10 11 14 ...
Страница 102: ...Maintenance 5 20 68P02963C70 O ...
Страница 103: ...MTH500 Detailed Service Manual COMPONENT BOARD LAYOUTS 68P02963C70 O 6 1 Component Board Layouts ...
Страница 104: ...MTH500 Detailed Service Manual COMPONENT BOARD LAYOUTS 6 2 68P02963C70 O This page intentionally left blank ...
Страница 109: ...MTH500 Detailed Service Manual Schematic Diagrams and Parts Lists 68P02963C70 O 6 7 Schematic Diagrams and Parts Lists ...
Страница 134: ...SCHEMATIC DIAGRAMS MTH500 Flex CD 6 32 68P02963C70 O This page left blank intentionally ...
Страница 140: ...Replacement Parts and Kits 6 68P02963C70 O ...
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Страница 142: ...Replacement Parts and Kits 8 68P02963C70 O ...
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