Sennheiser SK 100 G2 Service Manual page 13

Se- Type of measure-
quence ment/adjustment
3 RF module
See "Measuring set-up" page 10.
Removing the RF module:
1. Loosen the lens-head screw on the RF PCB (see exploded view, pos. 22).
2. Remove the RF module (maintain the motherboard connection via flat ribbon cable).
Re-establishing the ground connection between RF module and motherboard:
Connect the M6 point on the component side of the RF PCB and the P4 point on the component side of the motherboard.
For this purpose, solder a stranded wire with a length of 10cm between the points M6 and P4.
3.1 Supply voltage RF
PCB
3.2 Transmission
frequency
3.3 Measuring / balancing the PLL voltage
Attention
The buttons S204, S206, S202, and S208 on the motherboard may be damaged, if you press them using sharp-edged or
pointed objects (e.g. the tip of a ballpoint pen). Only use objects with end-rounded tips that will not damage the buttons.
3.3.1 Centre range limit
3.3.2 Lowest range limit
3.3.3 Uppermost range
limit
3.4 Measuring / balancing the RF output power
How to avoid measuring errors:
1. Desolder the antenna before starting the measurement.
2. Measure against a direct ground point on TP8.
3. Only use shielded measuring lines with an impedance of 50O and a length of 50cm.
3.4.1 Mean RF output
power
3.4.2 Highest RF output
power
3.4.3 Lowest RF output
power
3.5 Nominal deviation
LINE
3.6 Peak deviation LINE AF generator at jack
3.7 S/N ratio referring
to peak deviation
3.8 THD at nominal
deviation
SK 100 G2, SK 300 G2, SK 500 G2
02/2005
Signal input Device settings
Supply +2.4 V via „POWER" = ON;
DC
battery contacts (press button for approx.
3 seconds)
See 3.1 Pilot = „OFF"
Mute = Aus
See 3.1 Use „TUNE" to set the
centre transmission
frequency
See 3.1 Use „TUNE" to set the
lowest transmission
frequency
See 3.1 Use „TUNE" to set the
uppermost transmission
frequency
See 3.1 Spectrum analyser or
power measuring device;
set centre transmission
frequency (ft=fm)
See 3.1 Spectrum analyser or
power measuring device;
set highest transmission
frequency (ft=fh)
See 3.1 Spectrum analyser or
power measuring device;
set lowest transmission
frequency (ft=fl)
AF generator at jack Set „SENSIT" to -10dB
socket (1kHz, 270mV)
Set „SENSIT" to -10dB
socket (1kHz, 1.08V)
24kHz AF level meter
Mod: OFF MUTE= „ON"
See 3.4 AF level meter
THD measuring
Mod: ON
Mesuring Required
point/ test value
point
RF module +5.1V to
DC
TP72/GND
+5.35V
DC
Without Transmission
antenna at
frequency =
TP8/ direkt
receive
ground GND
frequency
±10kHz
TP3 +2.5V to
DC
+2.9V
DC
TP3 +0.9V to
DC
+2.3V
DC
TP3 +2.9V to
DC
+4.2V
DC
Without 15mW to
antenna to 38mW /
TP8 / direct 12dBm to
ground GND; 15.8dBm
Japan: J200 Japan: 5mW to
test socket 10mW / 7dBm
to 10dBm
See 3.4.1 < ±24kHz
See 3.4.1 < ±4kHz
Japan:
±40kHz
≤
See 3.4.1 60dB(A)
eff
See 3.4.1 0.08% to 1.2% –
Remarks
See page 27
See 3.4
Avoiding
measuring
errors
Balancing via
C114
Balancing via
C114
Balancing via
C114
–
Pay attention
to the pin
assignment of
the jack socket:
See "Measu-
ring set-up"
page 10.
–
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