Service manual

Shure LX2 Hand-Held Transmitter
Service Procedures21
25D1006 (CG)
Spurious Emissions and Current Drain: Domestic
SPECTRUM ANALYZER
+
–
J101
J102
L209
R217
Y201
C217
C216
I210
I2GN
C240
RF BOARD
SIDE 1
LX2 Transmitter
Spectrum Analyzer
Power supply: 9 Vdc Scale: 10 dB/div
Power switch: ON Start frequency: 10 MHz
Mute switch: MUTE Stop frequency: 1 GHz
Reference level: 20 dBm
Figure 12. 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 30 dB below the carrier level. If necessary,
retune C216.
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 C216, 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).