Orban Optimod-FM 8300 Operating Manual page 199

OPTIMOD-FM DIGITAL
the following pattern:
(1) + unreg.
(2) - unreg
Table 4-2: Layout Diagram of J7, with expected voltages on each pin
The +3.3V and +2.5V supplies are locally regulated on the DSP and base
boards (see Section 6).
C) Measure the regulated voltages at J7 with the DVM and observe the ripple
with an oscilloscope, AC-coupled. The following results are typical:
Power Supply Rail
+15VDC
–15VDC
+5VDC
–5VDC
Digital +5VDC
Table 4-3: Typical Power Supply Voltages and AC Ripple
3. Adjust Analog Output Level Trim.
A) Verify 8300 software controls are set to their default settings. [Refer to step
(1.B) on page 4-7.]
B) Feed the 8300 output with the built-in 400 Hz test tone:
a) Navigate to S
b) Set the M
C) Connect the audio voltmeter to the Left Analog Output.
D) Adjust output trim VR200 to make the meter read +10.0 dBu. (0 dBu = 0.775V
rms.) Verify a frequency reading of 400 Hz.
E) Verify THD+N reading of <0.05% (0.02% typical) using a 22 kHz low pass filter
in the distortion analyzer.
F) Set the M
ODE
B
YPASS
retains pre-emphasis.
G) Verify a reading (noise) of <–80 dBu at the output of the unit.
H) Using VR201, repeat steps (C) through (G) for the Right Analog Output.
4. Check frequency response of Analog I/O.
A) Verify 8300 software controls are set to their default settings. [Refer to step
(1.B) on page 4-7.]
B) Be sure you are still in B
C) Connect the oscillator to the Left Analog Input XLR connector.
(3) digital gnd
(4) chassis gnd
DC Voltage (volts)
.
/ T
ETUP EST
to T .
ODE ONE
to B .
YPASS
defeats all compression, limiting, and program equalization but
mode [see step (3.F)].
YPASS
(5) +15V (7) +5 V digital
(6) -15V (8) +5V analog
AC Ripple (mV p-p)
+15  0.5
–15  0.5
+5  0.25
–5  0.25
+5  0.25
[Obscured by noise]
MAINTENANCE
(9) –5V analog
(10) NC
<20
<20
<20
<20
4-9