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3-26
Maintenance:
Low Band Troubleshooting Charts
Level >
+2 dBm
Check signal at
collector of Q201
No
Yes
Check L204, L211, L212,
L215, C221, C228, C229,
C230,C231, C235,C297,
R204, R234, R238
Troubleshooting Flow Chart for VCO
Check signal at
collector of Q201
No RX LO or No
signal at U205 Pin 32
in RX
No TX LO or No
signal at U205 Pin 32
in TX
Level >
+10 dBm?
Check signal at
drain of Q203
Level >
-3 dBm?
Check signal at
drain of Q202 and
Q204
Level >
+7 dBm?
No
Yes
Replace Q201
Yes
Yes
Done
Check DC voltage
across R203
Problem
fixed?
Replace Q203
Check C215, C216,
L207, L208, L209,
U203
Level >
500 mV?
Check C200, C202, C203,
C222, C223, L201, L203,
TR201, CR202
Replace Q202
and Q204
Yes
Yes
No
No
No
No
Summary of Contents for PR860
Page 1: ...PR860 Two Way Portable Radio Detailed Service Manual ...
Page 2: ......
Page 5: ...iv Notes ...
Page 9: ...viii Table of Contents Notes ...
Page 13: ...Notes xii List of Figures ...
Page 17: ...1 4 Introduction Radio Model Information Notes ...
Page 51: ...2 34 Theory of Operation Voltage Control Oscillators VCO Notes ...
Page 81: ...4 4 Schematic Diagrams Overlays and Parts Lists Flex Layout Notes ...
Page 193: ...4 116 Schematic Diagrams Overlays and Parts Lists Low Band Section Notes ...
Page 196: ......