Sony DTV-01, Руководство пользователя

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Using LEDs inside the Set-back Box (“SBB”) as
troubleshooting tools.
There are four LEDs inside the SBB that can be used to identify certain
levels of functionality. The LEDs can be seen by looking through the
vent slots in the SBB top cabinet. Two are mounted on the tuner board
(also known as “Front-end” or “FE” board), and two are mounted on the
main board (also known as the DTV-98 board).
The red power LED on the DTV-98 board should be on whenever the SBB
is powered on by a control signal from the TV. In practice, the power LED
should be on whenever the I/O cable is connected and the TV is also
powered on.
Another red LED on DTV-98 board is the “heartbeat” LED, which should
be flashing at a steady rate whenever the SBB is on. This heartbeat indi-
cates that the operating program used to run the CPU in the SBB is run-
ning properly, i.e. the program is not locked up.
The two LED’s on the front-end board may be clear in color when they are
not lit, but when lit, one will be red and the other will be green. When the
SBB is receiving a valid DTV signal on the physical channel it is tuned
to, the green LED will be lit. The red led will light only when a valid DTV
signal is being received (green LED is lit) and errors in the received data
could not be corrected by the SBB’s error correction software. Very often,
a non-recoverable error (red LED on the front-end board flashed) will be
accompanied by a viewable abnormality in the picture (digital artifacts such
as pixelization, tiling, blocking, and freezing). The best installation is one
where the green LED is lit when the SBB is tuned to a valid DTV channel
and the red LED never illuminates