Tyco Electronics M/A-Com 19D902797G10, Руководство по обслуживанию

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TROUBLESHOOTING
4.0
TROUBLESHOOTING
4.1
TROUBLESHOOTING GUIDE
SYMPTOM AREAS TO CHECK INDICATIONS
1. Measure the transmitter output
power before the duplexer or
antenna switch (for simplex
mode).
The presence of power at this port
is an indication of a defective
duplexer, switch, or cables.
2. Measure the transmitter output
power before the low pass
filter.
The presence of power at this port
is an indication of a defective filter
or cables.
1. No Power or low Power at
Antenna Port.
3. Measure the transmitter output
power before the optional
isolator at the PA output port.
The presence of power at this port
is an indication of a defective
isolator or cables.
2. No power at PA output port
and PA ALARM is OFF.
Station is in receive mode.
1. No RF input to PA. Check
connection between PA and
TX
TX Synthesizer should deliver a
minimum of 10 Mw
2. Check the logic or DC inputs to
the PA from the Interface
Board through J201.
a. J201-2 PA KEY 5volts during transmit
b. J201-3 POWER SET 4 volts to 8 volts (4 volts
represents zero RF power)
c. J201-6 13.8 VF
13.8 Vdc
±
20%
3. No power at PA output port
and PA ALARM is ON
3. Defective PA Replace PA
4. Low power at PA output port
and PA ALRAM is OFF.
1. Low RF input to PA from TX
Synthesizer.
Power should be a minimum of 10
mW (10 dBm).
2. Check the voltage on J201-
3(POWER SET).
For minimal output power, this
voltage should be above 7 volts.
3. Check the power supply
voltage on the collector of Q1,
Q2 and Q3
Voltage should be minimal 13.4
Vdc.
4. One of the two final PA
transistors (Q2 or Q3) is
defective.
Replace the defective transistor.
5. Low power at PA output port
and PA ALARM is ON.
Check for over temperature
and/or a high VSWR condition
due to a mismatch at the
output port. The power control circuit protects
the PA by cutting back the power.
In case of a mismatch, refer to
symptom 1.
10 LBI-38674L
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