Technical Manual

10-33
Chart 33. 800 MHz DC Switch
800MHz DC Switch.
Voltage at
Q503-4?
Check
continuity
between U305
and Q503.
Refer to Chart
C.5 on "DC
Supply Problem".
Yes
No
Yes
No
No
No
MAEPF-24392-O
Yes
Yes
Yes
VDC at J1-17?
Check mating
plug. If plug is
good, go to
chart C.26.
VDC at U305?
Replace U305.
Voltage at
U305-1?
Check U503.
0V at Q503
Pin 5 - RX
Pin 3 - TX?
Chart 34. VHF/UHF DC Switch
No R5
U106 Pin 2
Voltage
at U106
Pin 8?
Voltage
at Q107,
Pin 2?
Voltage
at Q107,
Pin 3?
Voltage
at Q107,
Pin 4?
7.5V at
U202
Pin 8?
5V at
U102
Pin 1?
Less
than 4.8V
at U106
Pin 3?
Replace
U106
Check DC Power
Supply Failure
Chart C.5
Replace
Q107
Check L131,
L121 and CR109
and L122 For
Open Connections
YES
YES
YES
YES
YES
NO
NO
YES
NO
NO
YES
NO
NO
NO
Replace
U102
Replace
U202
No T5
Voltage
at Q111 Pin
3 collector?
Voltage
at U202,
Pin 8?
Replace
U102
Go to
Chart C.24
Replace
U202
Check Fuse,
Flex Connection
J1-15, 18, 20;
Volume Switch
Less than
4.8V at Q111
Pin 1 base?
5V at
U102
Pin 1?
Voltage
at U202
Pin 8?
Check
conn. J1,
R101, and
connector
good?
5V at
Pin 3
of U102?
Replace U202
Rectify
Fault
Replace
Q111
YES
NO
YES
YES
NO
YES
YES
NO
NO
NO
MAEPF-26044-O
NO
NO
YES
YES
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