Shure T1 Body-Pack Transmitters
13
Service Procedures
25C1016 (CC)
6. Connect the 50 Ω output cable to the frequency counter. If the
frequency is off by more than 5 kHz, adjust L209 to set the carri-
er frequency to
FC ±1 kHz.
7. Reconnect the 50 Ω output cable to the spectrum analyzer. Con-
firm that the output power remains within specification. If neces-
sary, readjust C217 and C215.
B: Spurious Emissions
1. Set the scale on the spectrum analyzer back to 10 dB/div.
2. Check the level of spurious emissions up to 1
GHz. Set the start
frequency of the spectrum analyzer to 10
MHz and the stop fre-
quency to 1
GHz. All spurs must be at least 35 dB below the
carrier level. If necessary, adjust C217 and C215 until the power
and spurious response are both within specification.
C: Current Drain
1. Using a milliammeter, make sure that the transmitter’s current
drain is less than 35 mA. If it is too high, try detuning C215, tak-
ing care that the power and spurious response remain within
specification.
2. Disconnect the power supply from the T1.
3. Unsolder the 50 Ω
RG174/U test cable, and resolder the antenna
lead to the RF board.
Audio Alignment
This section continues the procedures of the preceding subsections.
D: Gain
1. Reconnect the power supply to the T1, and set its Mute switch to
“On.”
Set the audio analyzer output as follows:
Frequency: 1 kHz
Amplitude: 70 mV
2. Connect the audio analyzer’s output to the transmitter’s micro-
phone input. Select the cable with the proper termination:
(a) T1: Tini
Q-G (quick-ground) connector
(b) T1G:
1
/
4
-in. phone plug
(c)
T1P: cable’s unterminated center conductor to pin 3 of
J104; shield to ground
3. Adjust the Gain pot (R125) for 775 mVac, ±10 mVac (0 dB,
±0.1 dBu) at
TP3 (turning counterclockwise increases the gain).
Record the voltage at this setting.
Note: At this point you may want to press the audio analyzer’s
Log/Lin button (to measure logarithmically) and activate the Ra-
