Shure U4D, Руководство по обслуживанию

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Shure U4D Dual Diversity UHF Receiver
12
25D1062 (AG)
Preliminary Tests
8. Make sure the tone key switch (S201) on the receiver rf-audio
board is in the ON position.The receiver should be muted. No
audio output should be present at the balanced and unbalanced
outputs.
9. Slide the tone key switch to the OFF position. J211 can be
accessed from the outside of the receiver and is marked
BALANCED LOW Z. With the audio analyzer in the Float
position, the audio voltage at balanced audio output J211 with
the switch at the LINE position (pin 2 and 3, unloaded) should
be as follows:
UA, UB MA, MB, MC, MD:
2.5
±
0.5 Vrms
KK: Not available at this time;
measurements will be available later.
II:
1.7
±
0.5 Vrms
10. J209 can be accessed from the outside of the receiver and is
marked HIGH Z. With the audio analyzer NOT in the Float
position, the audio voltage at unbalanced audio output J209
(pin 1 and 2, unloaded) should be as follows:
UA, UB,MA, MB, MC, MD: 1.25
±
0.25 Vrms
KK: Not available at this time;
measurements will be available later.
II: 0.837
±
0.25 Vrms
11. Set the rf signal generator Level to –105 dBm. The receiver
should be muted. No audio output should be present.
12. Connect a dc voltmeter to the center conductor (+) and the
ground (–) of receiver BNC antenna channel B input, marked
ANTENNA B IN. The measured voltage should be 12.0
±
0.5 Vdc.
13. Set the rf signal generator Level to –90 dBm, and connect it to
the receiver BNC antenna channel B input, marked ANTENNA
B IN. Be sure to use a dc block to protect the test equipment.
14. Repeat steps 7 through 11.
15. Return the tone key switch (S201) to the ON position.
16. Repeat the procedure on the second receiver.