User Guide

Issue 13, December 2020 Model 76D/77 User Guide
Page 46 Studio Technologies, Inc.
for Surround
“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 76D 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 76D’s
design to minimize the chance that clicks,
pops, or other objectionable audio signals
will be present on the monitor outputs.
A power-down circuit supplies the main
microcontroller integrated circuit with an
indication that a power loss is imminent.
When this condition is detected the monitor
outputs will switch to silence (digital audio
“black”) in preparation for a complete loss
of signal.
Power-Up Messages
Upon mains power being applied to the
Model 76D 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 76D 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 76d
5. Displays Model 76D’s main software
version
6. Displays
FPgA
7. Displays Model 76D’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 76D. The most likely cause would
be incorrect wiring of the data pair linking
the two units.
Error Code Err2
Err2 indicates that the Model 76D is hav-
ing problems with its internal logic device.
(A high-speed field-programmable gate
array (FPGA) serves as the digital “heart”
of the Model 76D and without it no audio
activity can occur.) The only way to rem-
edy this condition is to first try removing
and reconnecting mains power. (And that’s
a long-shot as to whether it would accom-
plish anything.) If Err2 continues to be
displayed the Model 76D must be returned
to the factory for service.
Error Code Err3
If a digital audio source with a sample rate
of other than 44.1, 48, 88.2, or 96 kHz is
connected Err3 will display and the mute
all function will be automatically enabled.
In this scenario, selecting a different
source that has a sample rate of 44.1, 48,
88.2, or 96 kHz will return the system to
normal operation.