Self-Diagnosis And Test Mode; Self-Diagnosis Mode For Servicing/Display Of History Of Dsp Errors - Sony SDP-EP9ES Service Manual

Self-Diagnosis and Test Mode

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.
1. Main Functions
• 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)
2. Entering the Test Mode
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. Ini-
tialization" on page 14.)
SECTION 3
TEST MODE
VOLUME LED
— 12 —
3. Self-diagnosis Mode for Servicing/Display of
History of DSP Errors
3-1. Self-diagnosis Mode for Servicing
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
• When an error is detected:
The error message is displayed for about 8 seconds on the fluores-
cent display tube, it is switched to "DOLBY SURROUND", 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.
• When no error is detected:
"software version X. XX" will be displayed, and the operation check
mode will be set. (X. XX means its version No.)
Table-1:
Error Message/Fluo-
rescent Display Tube
VOLUME LED blinks An unintended button is pressed, or connection
and fluorescent display
fault of flexible board between MAIN board and
tube is OFF* DISPLAY board.
Soldering fault or malfunction between IC202
EEPROM read error!
(MAIN board AT24C02) and IC201 (MAIN
board microprocessor).
Reached end of IC202 (MAIN board AT24C02)
EEPROM write error!
writing life or incorrect insertion of part.
Soldering fault between IC422 (MAIN part 1M
S-RAM access error!
SRAM) and IC423 (MAIN board SSP424023)
When a DSP error is detected
(Refer to "3-2. Display of History of Abnormal
DSP error detected!
DSP Operations".)
*NOTE:
Refer to "6. Check of Pressing of Unintended Button" on page 14.
Possible Reasons