OPTIMOD-FM DIGITAL
MAINTENANCE
4-9
the following pattern:
(1) + unreg.
(3) digital gnd
(5) +15V
(7) +5 V digital
(9) –5V analog
(2) - unreg
(4) chassis gnd
(6) -15V
(8) +5V analog
(10) NC
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
DC Voltage (volts)
AC Ripple (mV p-p)
+15VDC
+15
0.5
<20
–15VDC
–15
0.5
<20
+5VDC
+5
0.25
<20
–5VDC
–5
0.25
<20
D5VDC
+5
0.25
[Obscured by noise]
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
ETUP
/
T
EST
.
b)
Set the
M
ODE
to
T
ONE
.
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
to
B
YPASS
.
B
YPASS
defeats all compression, limiting, and program equalization but
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
YPASS
mode [see step (3.F)].
C)
Connect the oscillator to the Left Analog Input XLR connector.
Summary of Contents for 8300J
Page 1: ...Operating Manual OPTIMOD FM 8300 Digital Audio Processor Version 2 1 Software...
Page 7: ...Operating Manual OPTIMOD FM 8300 Digital Audio Processor Version 2 1 Software...
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Page 247: ...OPTIMOD FM DIGITAL TECHNICAL DATA 6 29...
Page 254: ...6 36 TECHNICAL DATA ORBAN MODEL 8300 CPU Module...
Page 260: ...6 42 TECHNICAL DATA ORBAN MODEL 8300 8300 RS232 BOARD PARTS LOCATOR...
Page 262: ...6 44 TECHNICAL DATA ORBAN MODEL 8300 8300 POWER SUPPLY PARTS LOCATOR...
Page 264: ...6 46 TECHNICAL DATA ORBAN MODEL 8300 8300 I O BOARD PARTS LOCATOR...
Page 270: ...6 52 TECHNICAL DATA ORBAN MODEL 8300 DSP BOARD PARTS LOCATOR DRAWING 32170 000 14...
Page 278: ...6 60 TECHNICAL DATA ORBAN MODEL 8300 8300 DISPLAY BOARD PARTS LOCATOR...
Page 279: ...OPTIMOD FM DIGITAL TECHNICAL DATA 6 61 DISPLAY BOARD...