How To Check The Rf Unit; Handset - Panasonic KX-FPC135 Service Manual

KX-FPC135 / KX-FPC141
4 HOW TO CHECK THE RF
UNIT
Factory supply only assembled RF unit for base unit and
Handset of KX-FPC135/KX-FPC141. (Factory does not supply
each parts on RF Unit.)
4.1.

Handset

1. Warm up the Marconi Radio Tester for at least 30 minutes
to allow internal crystal oscillation to become stable.
2. Refer to figures right for Handset wire connections.
3. Disconnect the Handset antenna from the PCB. If you allow
the antenna to remain and be a load, the readings will be
wrong.
4. Supply DC 3.9V Handset PCB using a DC power supply.
5. Solder RF cable to TP-ANT and TP-GND and connect BNC
side to Marconi. Use 100 W max. RF Input.
6. Press TALK, then press "5", "8" and "0" simultaneously.
7. Press TALK. (Base Unit power is off)
4.1.1. Carrier frequency check:
1. Set Marconi to Transmit Test (press TX TEST button).
2. Check TX Frequency =926.100 MHz+/-3.0 kHz.
3. When value if off, adjust VRfreq.
4. If can´t adjust replace RF Unit.
4.1.2. Transmit power check:
1. Press dBm button on Marconi.
2. Check Marconi TX Power reading. It should equal
-3.5 dBm+/-4 dBm (-7.5 dBm ~ +1.5 dBm).
3. When value is over, replace RF Unit.
4.1.3. Receiving sensitivity check:
1. Connect audio cable BNC side to AF INPUT in Marconi and
other side to TP-AF and TP-GND.
2. Set Marconi to RX TEST mode. Enter the following setting:
a. Frequency = 902.100 MHz
b. Level = 60 dBµV
c. Set Modulation = 1.000 kHz
d. Level = 6.000 kHz
3. Press the SINAD button on Marconi until the display shows
SINAD value. Press the dB button.
4. Press the RF GEN and LEVEL button.
5. Using the VARIABLE knob on Marconi decrease RF GEN
LEVEL value until SINAD value is 12 dB.
6. Check the RF GEN LEVEL. This should be less than
+1 dBµV(+7 dBµVemf). When value is over, replace RF
Unit.
4.1.4. Squelch check:
1. Connect scope probe (X1) lead to TP-SQ, negative to TP-
VSS and BNC end to scope.
2. Set scope to the following codition: TIME/DIV = 1 msec,
VOLT/DIV = 1 V
3. Set RF GEN LEVEL to +5 dBµV(+11dBµVemf). Check
scope voltage is LOW.
4. Set RF GEN LEVEL to -17 dBµV(-11dBµVemf). Check
scope voltage is HIGH.
5. When scope voltage is wrong, replace RF Unit.
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