Shure UC2, Руководство по обслуживанию

Страница: 14 / 34

Shure UC2 Hand-Held UHF Transmitter
14 Service Procedures 25A1044 (RI)
Alignment
Use this service procedure to correctly align the transmitter’s
operating (output) frequency. C510 tunes the voltage-controlled
oscillator (VCO) to the operating frequency selected, with a 1 – 4 Vdc
tuning range.
C314 adjusts the reference oscillator on the synthesizer, U304.
AUDIO ANALYZER
RETAINING
RING
TEST
HEAD
FREQUENCY COUNTER
J205
J205 S200
AUDIO SIDE 1
TPRF1
C347
RF SIDE 2
CH 2
CH 1
UC2 Transmitter Audio Analyzer Frequency Counter
Power (S200): ON (+9 Vdc) Measurement: AC level Operating freq: See Table 2
Operating freq: See Table 2 Filters: Connect CH 2: TPRF1 and GND
Gain: Minimum Low-Pass (30 kHz): ON For JA,JB frequencies:
Connect to J2
High-Pass (400 Hz): ON
Connect to J2
(pcb rf side 1)
Figure 6. UC2 Frequency Alignment Set-Up
1. Remove C347 and connect a 50
Ω
cable between TPRF1 /
RF GND and a frequency counter.
For JA, JB frequencies, do not remove C347. Connect a
“rocket launch” cable between J2 and the frequency counter.
J2 is only placed on the JA, JB frequency assemblies.
2. Use a PT1840 test head and brass ring (PT1838-Y) to connect
the audio analyzer to the UC2 audio input (J205). Turn ON the
Low-Pass (30 kHz) and High-Pass (400 Hz) filters on the audio
analyzer.
For bench testing, the audio analyzer can be directly connected
to the contact board gold contacts with clip leads.
3. Toggle the power switch, S200, to turn on the UC2 transmitter.
4. Set the UC2 Group and Channel switches, S301 and S302,
according to the group designators on the board and the
settings given in Table 2.