Service manual

Shure LX2 Hand-Held Transmitter
24
Service Procedures
25D1006 (CG)
Spurious Emissions and Current Drain: Euro
SPECTRUM ANALYZER
+
–
+
–
J201
J202
J201
J202
RF BOARD (TOP)
ETSI
RF BOARD (BOTTOM)
ETSI
TP8
TP9
TP6
TP7
TP5
TP3
4TP
5
TP2
TP1
L201
R217
Y201
C214
C216
C222
C226
LX2 Transmitter
Spectrum Analyzer
Power supply: 9 Vdc Scale: 10 dB/div
Power switch: PWR Start frequency: 10 MHz
Mute switch: MUTE Stop frequency: 1 GHz
Reference level: 20 dBm
Figure 15. Spurious Emissions and Current Drain Test Set-Up
1. Set the spectrum analyzer as follows. Set the scale to 10 dB/div,
the start frequency to 10 MHz, the stop frequency to 1 GHz, and
the reference level to 20 dBm.
2. Check the level of spurious emissions. All spurious emissions
must be at least 44 dB below the carrier level. If necessary,
retune C226.
3. With a digital multimeter, measure the current drain of the
transmitter: it should be less than 35 mA. If it is too high, try
detuning C226, but make sure that the power and spurious
response remain within specification.
4. Check that 9 Vdc (±0.35 Vdc) is present at the head board
+9 V location (I133 on the audio board).