Preliminary Tests - Shure T1 Service Manual

Preliminary Tests

Listening Tests
Functional Tests
RF
Tests
Audio Tests
25C1016 (CC)
Before disassembling the unit, operate it to determine whether it is
functioning normally.
Focused Testing: First and most important: Review any customer
complaint or request and focus your listening and functional tests on any
reported problem. For example, for "short range" and "drop-outs" com-
plaints, perform only the
there is a strong indication that the customer is using the product incor-
rectly (e.g., not keeping the transmitter in the receiver's line of sight, not
avoiding metal enclosures or TV interference). Return the unit to the cus-
tomer together with an explanation of the proper set-up procedures.
For complaints of distortion or other audio problems, try a "standard"
lavalier or headset microphone (you should have one of each micro-
phone on-hand for testing) and perform the audio tests in this section.
1. Remove the case top, mute the audio, and apply 9 Vdc to the
battery terminals.
2. Measure the current drain: it should not exceed 35 mA.
3. Maximize the signal received on the spectrum analyzer by at-
taching a telescoping whip antenna to it. Then measure the
near-field output power: it should be 7 dBm.
(If you are unsure of the results you obtain here, measure the
output power conductively by soldering a 50 Ω cable to the out-
put of the transmitter. Verify that the output power is 15 dBm,
2 dBm.)
4. Verify that the carrier frequency of the transmitter varies from its
nominal value by no more than "6 kHz.
5. Check for an intermittent problem by shaking the transmitter and
tapping on it. As you do so, try to keep it at a constant distance
from the spectrum analyzer. Verify that the output power on the
spectrum analyzer shows no large and sudden drops in power
level (it will, however, vary a few dB with hand position).
6. Turn off the transmitter.
If the transmitter passes the above tests, its
working as designed.
A: Verify the Matching Receiver
1. Connect the signal generator to the receiver through a 50 Ω
cable. Tack-solder the center conductor to the antenna input and
ground the shield of the cable to pcb ground.
5
Shure T1 Body-Pack Transmitters
tests in this section. If the unit passes these,
RF
circuits are
RF
Preliminary Tests