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August 16, 2007
6816985H01-B
6.4-18
700/800 MHz Troubleshooting Charts:
700/800 MHz Frequency Generation Unit Troubleshooting Chart
6.4.19700/800 MHz Frequency Generation Unit Troubleshooting Chart
MAEPF-27346-O
FGU NoLO
Injection/TX
Unlock
For RX check C263,
L258, C267, C261,
R293 and R294 for
continuity.
For TX check C278,
L274, C276, C279,
R273, R274 and R275
Change U250
Replace Y200
and/or C214
Check
U201 circuitry
Replace
U202
Fix/replace
U201
Do a continuity
check and refer to
DC switch chart
Replace
U202
Do a continuity
check and refer to
DC switch chart
Replace
suspected
component
Is Vdc at
D251&D252(RX VCO)
D270(Tx VCO)
0.4<Vdc<12?
Is Vdc at
R259,
High for Tx,
Low for Rx mode
No
Take a continuity
check of traces
to U201
No
No
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Is Vdc
at C218 3V?
and C211
5V?
Is there
a voltage reading
at R204, R205, C206,
C207 directed
to U202?
Is Vdc
at Y200 pin 4
3V?
Do you
see 16.8MHz at
pin 3 of Y200 and C214
connection to Xtal
K9 pin of
U202?
Do
you see
16.8MHz at
C245?
Do
you see
~11.5 Vdc at pin 2
of D202?
Replace
U202
Yes
Is
3Vdc at
pin 4 of
D201?
Check components
D201, D202, C206,
C207, C208
and C209
For TX only pin 3 of Q216 (TX)
Summary of Contents for ASTRO MT 1500
Page 4: ...iv Table of Contents August 16 2007 6816985H01 B Notes ...
Page 164: ...August 16 2007 6816985H01 B 5 6 Troubleshooting Procedures Operational Error Codes Notes ...
Page 188: ...August 16 2007 6816985H01 B 6 1 24 VHF Troubleshooting Charts Secure Hardware Failure Notes ...
Page 212: ...August 16 2007 6816985H01 B 6 2 24 UHF1 Troubleshooting Charts Secure Hardware Failure Notes ...
Page 236: ...August 16 2007 6816985H01 B 6 3 24 UHF2 Troubleshooting Charts Secure Hardware Failure Notes ...
Page 710: ...9 2 40 UHF1 Schematics Board Overlays and Parts Lists August 16 2007 6816985H01 B Notes ...
Page 806: ...9 5 32 900MHz Schematics Board Overlays and Parts Lists August 16 2007 6816985H01 B Notes ...
Page 816: ...Index 4 August 16 2007 6816985H01 B Notes ...
Page 817: ......