Sony WCS-880, Service Manual

Page: 6 / 24

6
WCS-880
SECTION 3
ELECTRICAL ADJUSTMENTS
0 dBm = 1 mW, 0 dBV = 1 Vrms
TX SECTION
1. Consumption Current Check
Setting:
Procedure:
1. Connect a regulated dc power supply (1.5 V) and ampere meter.
2. Check that the value of ampere meter satisfy specified value.
Specified value: 50 mA to 60 mA
2. TX OSC (12.8 MHz) Adjustment
Setting:
Procedure:
1. Connect a frequency counter to the TP53 on TX BASE board
and the foot of VCO board shield case.
2. Set the
[RF CHANNEL]
switch (SW51) to
[2]
.
3. Adjust CT2 on the TX BASE board so that the value of
frequency counter becomes 12.794 MHz.
Specified value: 12.794
±
0.001 MHz
3. TX Frequency Confirmation
Setting:
Procedure:
1. Connect the 1/4
λ
sleeve antenna to a frequency counter, and
put the antenna by the lead wire antenna (ANT1).
2. Set the
[RF CHANNEL]
switch (SW51) to
[1]
.
3. Confirm that the value of frequency counter satisfy specified
value.
4. Change the
[RF CHANNEL]
switch (SW51) to
[2]
.
5. Confirm that the value of frequency counter satisfy specified
value.
6. Change the
[RF CHANNEL]
switch (SW51) to
[3]
.
7. Confirm that the value of frequency counter satisfy specified
value.
Specified values: CH-1: 863.33 MHz to 863.47 MHz
CH-2: 864.13 MHz to 864.27 MHz
CH-3: 864.53 MHz to 864.67 MHz
Note: Tool
•
1/4
λ
sleeve antenna
Production procedure:
1. Cut about 80 mm of the outer cover at the other end of an
approximately 2 meter coaxial cable (1.5D-2V or the equiva-
lent) with a BNC connector.
2. Pull back the outer cover and fold the wire mesh over the out-
side cover.
3. Cover the folded back wire mesh (outer cover) with a tube (for
example, heat shrink tube) and fasten.
4. Preparation of 1.50 - 2 V coaxial cable
80 mm
BNC
80 mm
80 mm
BNC
BNC
The WCS-880 is a wireless microphone system operating in the 800
MHz. This system comprises the transmitter unit and the receiver unit.
+
–
regulated dc
power supply
mA
Set
battery
terminal
#
battery
terminal
3
frequency counter
lead wire antenna (ANT1)
1/4
λ
sleeve antenna
TX BASE
board
TX BASE board
TP53
+
–
frequency counter
Foot of VCO board
shield case
4 mm 6 mm
Mesh
80 cm
BNC