Model 760-03/77 User Guide
Issue 4, October 2016
Studio Technologies, Inc.
Page 47
for Surround
If during normal operation the sync source
changes from one valid rate to another a
visual indication is provided. On the Model
77 units the new sample rate—
32.0
,
44.1
,
48.0
,
88.2
,
96.0
,
176.4
, or
192.0
—will mo-
mentarily be displayed.
Any time that a valid sync signal is not
connected to the Model 760-03 the digital
monitor output will automatically revert
to an internally generated sample rate of
48 kHz with no digital audio content pres-
ent. This audio “black” signal will allow most
connected equipment to continue to func-
tion correctly, of course with no meaningful
audio signal present. As soon as a valid
sync signal is again connected to the Model
760-03 the monitor outputs will automati-
cally switch to their correct sample rate and
audio signals will again be present.
Power Down
Great care was taken in the Model 760-03’s
design to minimize the chance that clicks,
pops, or other objectionable audio signals
will be present on the post-fader digital
and analog monitor outputs. A power-down
circuit supplies the main microcontroller
integrated circuit with an indication that a
power loss is imminent. When this condi-
tion is detected the digital monitor outputs
will switch to silence (digital audio “black”)
in preparation for a complete loss of signal.
Electromechanical relays associated with
the analog monitor outputs will change to
their mute state to minimize the chance of
signal transients reaching the connected
loudspeaker inputs.
Power-Up Messages
Upon mains power being applied to the
Model 760-03 all connected Model 77
units will go through a power-up sequence.
The sequence starts by each of the indi-
vidual LEDs lighting in a “walk-through”
sequence. Then the 4-digit display tests all
its LED segments. Finally, a set of mes-
sages provide details on the specific Model
77 and connected Model 760-03 software
versions:
1. Displays
77
2. Displays Model 77’s software version
3. Displays Model 77’s unit address
(
A1
,
A2
,
A3
, or
A4
)
4. Displays
760
5. Displays Model 760-03’s main
software version
6. Displays
FPgA
7. Displays Model 760-03’s logic
device (FPGA) software version
After a successful system power-up
sequence normal operation will then
commence.
Error Codes
Should a problem be encountered during
power up one of four error codes may
show on the Model 77’s 4-digit display.
Error Code Err1
Err1
indicates that communication is not
taking place between the Model 77 and the
Model 760-03. The most likely cause would
be incorrect wiring of the data pair linking
the two units.
Error Code Err2
Err2
indicates that the Model 760-03 is
having problems with its internal logic
device. (A high-speed field-programmable
gate array (FPGA) serves as the digital
“heart” of the Model 760-03 and without
