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This unit is provided with a “self-diagnosis and self-recovery func-
tion” which detects DSP errors and automatically recovers the unit,
and a test mode for performing operation checks during repairs.

• DSP self-diagnosis and self-recovery function
• Self-diagnosis for servicing and error message display
• Display of history of past DSP errors
• Various operation check mode
• SRAM, EEPROM check function
• Initialization (Differs according to country)

1. While pressing the  AC-3 RF  button and  DIGITAL 2  button

simultaneously in the power OFF state, press the  POWER  but-
ton.

2. When the VOLUME LED starts blinking, release these buttons.

The self-diagnosis for servicing will be executed, and the opera-
tion check mode will be set.
(NOTE: Performing initialization will erase the error history.
Do not therefore press the wrong buttons. For details, refer to
“5. Initialization” on page 15.)

Before entering the test mode, first the following self-diagnosis pro-
gram for servicing will be run.

1. Checks if unintended buttons are being pressed
2. Checks EEPROM (External memory device) operation
3. Read/write test of DSP external memory (1M SRAM)
4. Checks and displays history of various DSP abnormal operations

The error message is displayed for about 8 seconds on the fluo-
rescent display tube, it is switched to “MPEG/DOLBY DIGITAL”,
and the operation check mode is set. (See Table 1.)
When several errors occur at the same time, only the first error
detected will be displayed.

“Ver. main X. X mpeg X. X” will be displayed, and the operation
check mode will be set. (X. X means its version No.)

Error Message/Fluo-
rescent Display Tube

Possible Reasons

VOLUME LED blinks
and fluorescent display
tube is OFF*

An unintended button is pressed, or connec-
tion fault of flexible board between MAIN
board and DISPLAY board.

EEPROM read error!

Soldering fault or malfunction between IC202
(MAIN board AT24C02) and IC201 (MAIN
board microprocessor).

Reached end of IC202 (MAIN board
AT24C02) writing life or incorrect insertion
of part.

*NOTE:
Refer to “6. Check of Pressing of Unintended Button” on page 15.

Soldering fault between IC422 (MAIN part 1M
SRAM) and IC423 (MAIN board SSP424023)
When a DSP error is detected

(Refer to “3-2. Display of History of Abnormal
DSP Operations”.)

VOLUME LED

EEPROM write error!

S-RAM access error!

DSP error detected!

– 14 –

• When “DSP error detected!” is displayed on the fluorescent dis-

play tube, the history of DSP errors will be displayed eight seconds
later. (See Fig. 1.)

• This history will be displayed if a DSP error has occurred in the

past. It helps the detection of malfunction parts by enabling past
problems of the unit to be checked.

• This history shows the “Cause of error” and “How many times

occurred” for the two DSPs. (See Fig. 1.)

Corresponding DSP

Contents of fluores-
cent display tube

: 1st DSP (DSP56009)

2nd DSP (SSP424023)

:

1 2 3 x 0 0 0 0

1 2 3 x 0 0 0 0

↑

↑

4

↑

3

↑

2

↑

1

↑

4

↑

3

↑

2

↑

1

:

How to read the
display

• During the operation check mode, functions can be set by press-

ing the corresponding button. (See Table-3.)

• Each time a button is pressed, the corresponding function will be

displayed for about 8 seconds.

• Buttons other than those displayed in Table-3 operate usually.
NOTE: Do not press the  SET UP  button during the operation

check mode. As this button is provided with a special
function for debugging, pressing it may impede the normal
output of signals in the sub-woofer mode.

Button

Function

Outputs the Lch DIGITAL-2 input signal
to the REAR Lch and the Rch to the REAR
Rch.

Fluorescent
Display Tube
Display

Outputs the Lch DIGITAL-3 input signal
to the CENTER and the Rch only to the
WOOFER.

Outputs the Lch DIGITAL-4 input signal
to the FRONT Lch, REAR Lch, CENTER,
and the Rch to the FRONT Rch, REAR
Rch, and CENTER.

DIGITAL2

DIGITAL3

DIGITAL4

OFF

DIG-2
(L-SL, R-SR)

DIG-3
(L-C, R-SW)

DIG-4
(L, R-ALL)

Whole fluorescent display tube lit check
Each time the button is pressed, the fluorescent display tube
lights up as follows.
Lit totallynLit partially 1nLit partially 2nLit totally....

By pressing the  MENU  knob and displaying “<<< LEVEL ADJUST >>>”,
and rotating the  +/–  knob to the right, the input signal selected at that time
can be output to any Lch or Rch channel.
(See Table-4.)

Fluorescent Display
Tube Display

Output Destination of Input Signal

Outputs the FRONT Lch/Rch signal only to
the REAR Lch/Rch.

Outputs the FRONT Lch signal only to the
REAR Lch, and FRONT Rch signal to the
REAR Rch.

Outputs the FRONT Lch/Rch signal to the
FRONT Lch/Rch, the REAR Lch/Rch signal
to the REAR Lch/Rch, the CENTER signal to
CENTER,  and the WOOFER signal to
WOOFER as usual.

Outputs the FRONT Lch signal to the FRONT
Lch, REAR Lch, and CENTER, and the
FRONT Rch signal to the FRONT Rch, the
REAR Rch, WOOFER.

Exchange (L-SL, R=SR)

Exchange (L-C, R=SW)

Exchange (NORMAL)

Exchange (L, R-ALL)

Number of times the error has occurred

↑

• The left side shows the errors of the first DSP (DSP56009:MAIN

board IC424) and the right side shows the errors of the second
DSP (SSP424023:MAIN board IC423).

• The “How many times occurred” indicates the number of times

that the error has occurred. If an error has occurred more than
256 times, it will be displayed as 256.

• The 

1 2 3 4 part shows 0 or 1 according to the cause of the

error. If an error has occurred, 1 will be displayed. If no error has
occurred, 0 will be displayed. (See Table-2.)

Cause of error

Possible cause

Mostly due to faulty connection (soldering) be-
tween DSP and microprocessor

Faulty DSP clock (X401 and onwards), faulty
DSP part, etc.

Overrunning of DSP due to heat, microproces-
sor bugging, or IC301 (MAIN board PLL) is
faulty

Faulty DSP part, or faulty microprocessor part,
etc.

1 Failed in initial

booting

2 DSP does not

operate

3 Communication

port malfunction

4 No reply from DSP

NOTE: This history is memorized in the EEPROM until the unit

is initialized. (Refer to “5. Initialization” on page 15.)

– 15 –

After executing the test mode, be sure to perform initialization.

While pressing the  AC-3 RF  button and  DIGITAL3  buttons
simultaneously, press the  POWER  button. When the VOLUME
LED starts blinking, release the buttons. “initialized (J/SP/AEP)”
will be displayed on the fluorescent display tube, and all internal
settings will be returned to the initial values.

While pressing the  AC-3 RF  button and  DIGITAL4  buttons
simultaneously, press the  POWER  button. When the VOLUME
LED starts blinking, release the buttons. “initialized (U/CA)” will
be displayed on the fluorescent display tube, and all internal set-
tings will be returned to the initial values.

NOTE: As all histories of abnormal DSP operations will be erased,

note down the contents of the history beforehand.

• This check is always performed when the power is turned ON.

Therefore when an error occurs, it can be known without setting
the test mode because the VOLUME LED blinks and the fluores-
cent display tube stops displaying.

• When an unintended button is pressed during the test mode or

initialization, the VOLUME LED also blinks, and the fluorescent
display tube stops displaying, preventing no mode to be set.

In the personal use of the unit at home, if no sounds are produced
due to DSP problems, the DSP will be rebooted automatically to
attempt recovery. If no sounds are still produced after five retries,
“Turn POWER SW off!” will be displayed on the fluorescent display
tube.
If this problem occurs, it indicates that the DSP is faulty or the
user’s setting environment may be unsuitable. Refer to “3. Self-
Diagnosis Mode for Servicing/Display of History of DSP Errors”
on page 13 to identify the problems.

– 16 –

AC1 board

AC2 board

SW board

PS board

DISPLAY board

VOL board

MAIN board

TR board

DECODER board