Studio Technologies 76DA V.4.12 - Manual (Page 47)

Model 76DA/77 User Guide Issue 9, May 2014
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
momentarily be displayed.
Any time that a valid sync signal is not
connected to the Model 76DA the monitor
outputs will automatically revert to an inter-
nally generated sample rate of 48 kHz with
no digital audio content present. This audio
“black” signal will allow most connected
equipment to continue to function correctly,
of course with no meaningful audio signal
present. As soon as a valid sync signal is
again connected to the Model 76DA the
monitor outputs will automatically switch to
their correct sample rate and audio signals
will again be present.
Power Down
Great care was taken in the Model 76DA’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 76DA all connected Model 77 units
will go through a power-up sequence. The
sequence starts by each of the individual
LEDs lighting in a “walk-through” sequence.
Then the 4-digit display tests all its LED
segments. Finally, a set of messages
provide details on the specific Model 77 and
connected Model 76DA 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 76DA
5. Displays Model 76DA’s main software
version
6. Displays FPgA
7. Displays Model 76DA’s logic device
(FPGA) software version
After a successful system power-up
sequence normal operation will then
commence.
Error Codes Err1 and Err2
Should a problem be encountered during
power up one of two error codes may show
on the Model 77’s 4-digit display. If Err1
displays it indicates that communication is
not taking place with the Model 76DA. The
most likely cause would be incorrect wiring
of the data pair linking the two units. Err2
indicates that the Model 76DA is having
problems with its internal logic device. (A
high-speed field-programmable gate array
(FPGA) serves as the digital “heart” of the
Model 76DA and without it no audio activ-
ity can occur.) The only way to remedy
this condition is to first try removing and
reconnecting mains power. (And that’s a
long-shot as to whether it would accomplish
anything.) If the error code continues to be
displayed the Model 76DA must be returned