25
DSP/Amplifier PCB LED’s
There are 2 LED’s in the system, located on the DSP/Amplifier board, a green LED (DS6500
[sheet 3, D7]) and an amber LED (DS6501). The amber LED is not populated in production.
When the main board is installed and rear cover is in place, the light produced is visible (with
practice) through the rear grille as it reflects off the heat sink as well as goes through drilled
holes in the PC board. R6500 and R6501 limit the current through the LED’s (as well as the
DSP controlling them). The table below explains the uses of these LED’s in production mode
(CB = Counter Blink: when one LED is on, the other LED is off!):
THEORY OF OPERATION
Green
LED
Amber
LED
Description
Off
Off
This should never happen. If it does, it likely means
1) That there is no power –OR-
2) There is a problem with the hardware (or, perhaps, software!)
Off
On
When power is first supplied, BEFORE the DSP boots, the hardware
will put the LED’s into this state. If the board stays in this state
there is a problem with the DSP hardware (or software).
CB, 5 Hz
CB, 5 Hz Immediately after powering up AND if the LED’s remain in this mode,
there is a problem with the Power On Self Test (POST): either the
FLASH did not checksum or the SDRAM memory test failed or
there was a problem initializing one or more or the audio peripherals
(U4000, U4400).
Once
every 5
sec
Off
Board is powered, initialized, and waiting for a Smart Speaker
command to turn on the board. The LED will be on for only 0.010
seconds!
1 Hz
Off
Board is powered, initialized, has been turned on by the console (or in
ASCII TAP mode) and S/PDIF is present. When on, the LED will be
on for 0.5 seconds.
CB, 1 Hz
CB, 1 Hz Board is powered, initialized, has been turned on by the console (or in
ASCII TAP mode), S/PDIF NOT present. When on the LED will be
on for 0.5 seconds.
Toggle Don’t
care
The green LED will toggle whenever a byte is received from the
RS-232 input. This toggling will modulate the current state of the
green LED, i.e. the normal 1 Hz rate may be “chopped” by incoming
RS-232 data.
CB, 5 Hz
CB, 5 Hz If the board passed the POST and generally seemed to be OK, this
state indicates that a catastrophic software error has occurred. The
production code will stay in this mode for 1 second then do a
software reset; development code will remain in this state, allowing
the developer to isolate the source of the problem.
X
ON
When the system is operating normally, the orange LED may remain
on when the amplifier mute is on.
1 Hz
1 Hz
LED’s will blink together when reading FLASH update data.
5 Hz
5 Hz
LED’s will blink together when FLASH is being written with update
information
10 Hz
OFF
The green LED will blink when in the quasi-standby state
