Tait TB8100 Service Manual

92 Reciter Fault Finding TB8100 Service Manual
© Tait Electronics Limited September 2006
Task 2 —
Check Audio Output
Using External
Signal
1. Inject an RF test signal (1kHz audio, 60% modulation) of the
required frequency at –80dBm (22.4µV) into the antenna input.
2. Run the Service Kit and connect to the reciter. Put the reciter in
Standby mode. Select Diagnose > Reciter > Audio I/O and check
that the measured output level is the same as the level displayed on the
Audio Output gauge.
Note The gauge will display the audio level of the balanced or unbal-
anced line out, whichever is selected in the profile of the currently
selected channel. The Level box displays the line sensitivity of the
currently selected channel. The audio output will be set to this
level during this test.
If the levels are correct, go to Task 3
. If they are incorrect, recali-
brate the line levels using the Calibration Kit and repeat the test. If
the line levels are now correct, go to Task 3
.
If the line levels are still incorrect, either the digital board or system
interface board is faulty. If the measured output voltage is greater than
the voltage displayed on the gauge, go to Step 3. If the measured out-
put voltage is less than the voltage displayed on the gauge, go to
Step 4.
3. Measure the audio voltages at the following test points on the digital
board:
balanced line out IC1020 pin 1
IC1026 pin 1
unbalanced line out IC1005 pin 1
IC1026 pin 7.
Both voltages should be approximately 1V
pp
. If the voltages are
greater than 1V
pp
, the digital board is faulty. Return the complete
reciter to your nearest CSO for repair or replacement. If the voltages
are 1V
pp
or less, replace the system interface board.
4. Measure the audio voltages at the following test points on the digital
board:
balanced line out IC1020 pin 1
IC1026 pin 1
unbalanced line out IC1005 pin 1
IC1026 pin 7.
Both voltages should be approximately 1V
pp
. If the voltages are 1V
pp
or higher, replace the system interface board. If the voltages are less
than 1V
pp
, the digital board is faulty. Return the complete reciter to
your nearest CSO for repair or replacement.

Tait TB8100 Specifications

General

Brand	Tait
Model	TB8100
Category	Accessories
Language	English