DOWNLOAD Sony SCD-XB790 Service Manual ↓ Size: 5.78 MB | Pages: 78 in PDF or view online for FREE

13

TRACKING command (4X): Tracking servo related.

No.

Name

Description

Remarks

41

TGAIN NM/UP

The tracking servo gain is switched between normal and up

Normal or up are switched alternately

44

ADJ TRK DSP

The traverse AGC and E-F balance adjustment is performed

45

TRACKING AGC

The tracking servo gain is adjusted automatically

SEARCH command (5X): Track search related. (Nos. 51 through 53 are not used for the servicing.)

No.

Name

Description

Remarks

51

1-TRCK JUMP

One-track jump is performed

52

FINE SEARCH

Fine search is performed

53

M-TRCK MOVE

M-track movement is performed

DISC DETECT command (6X): Disc type check related.

No.

Name

Description

Remarks

Disc type check is executed
Display after judgment

61

DISC DETECT

DSKMOD CD: Judged as CD

Refer to how to apply servo by manual

DSKMOD SL: Judged as SACD (SL)

operation (See page 14)

DSKMOD DL: Judged as SACD (DL)
DSKMOD HYB: Judged as HYBRID

62

CD SETTING

Enter disc type    CD setting

CD forced setting

63

SL SETTING

Enter disc type    SL setting

SL forced setting

64

DL SETTING

Enter disc type    DL setting

DL forced setting

6F

Download

Not used for the servicing

LASER command (7X): Laser of optical pick-up related.

No.

Name

Description

Remarks

7A

ADDTIME CD

Cumulative light emission time of the laser for CD is displayed
 (Initialized by 8D command)

7B

ADDTIME HD

Cumulative light emission time of the laser for SACD is displayed
 (Initialized by 8D command)

7C

FJUMP TEST

Not used for the servicing

TOOLS command (8X): Performs aging, reads adjusting parameters, etc.

No.

Name

Description

Remarks

81

VERSION

Firmware version is displayed

Example: Ver 1.00

83

TRAY AGING

Tray open-close aging is performed

Not used for the servicing

87

DISP ADJ DT

Automatic adjusting parameters are displayed via RS-232C

Not used for the servicing

8A

FL CHECK

Display of fluorescent indicator tube and keys are checked

8D

SETUP MODE

Set to factory shipping mode

Set when repair completed

PLAY MODE, etc. are initialized

Refer to 4-5. SHIPPING MODE (See page 17)

QA command (9X)

No.

Name

Description

Remarks

91

FJUMP CHECK

The focus jump is checked

Not used for the servicing

92

SET CHECK

The set is checked

Refer to 4-3. SET CHECK (See page 15)

93

WATER MARK

Not used for the servicing

94

SET AGING

The set aging is performed

Not used for the servicing

Repeat by the specified number of times or until an error occurred

95

FJMP CHK BU

The focus jump is checked (for jig)

Not used for the servicing

9C

BU DENCHO

The S curve waveform, traverse waveform, and RF waveform can be

Refer to 4-6.WAVEFORMS CHECK

checked successively

(See page 17)

9D

PLAY&RFD ON

SACD playback, RFD output

Not used for the servicing

SACD jitter measuring mode

9E

RFD ON/OFF

RFD output is turned on or off

Not used for the servicing

SACD jitter measuring mode

IC command (AX)

No.

Name

Description

Remarks

A0

IC SELF CHK

Each IC and its communication are checked

Normal or up are switched alternately

14

In analyzing failures of the set, the servo may be applied by manual
operation. To apply servo in the test mode, use the following
method.
1. After setting the test mode, rotate the 

[        AMS        ]

 dial to

select a command, and press the 

[        AMS        ]

 dial to enter.

2. “61 DISC DETECT” (Disc type check)

t“18 ALL SRV ON”

(All servos on + auto adjustment)

3. If applying servo while checking the condition one by one,

“61 DISC DETECT” (Disc type check)

t“31 PI/FE OFSET”

(Offset automatic adjustment)

t“14 FSRV ON/OFF” (Focus

servo on)

t“16 CLV ON/OFF” (CLV servo on)t“44 ADJ

TRK DSP ” (E-F balance adjustment)

t“15 TSRV ON/OFF”

(Tracking servo on)

t“17 SSRV ON/OFF” (Sled servo

on)

t“24 ADJ FCSBIAS” (Focus bias adjustment)t“27

FOCUS AGC” (Focus auto gain adjustment)

t“45

TRACKING AGC” (Tracking auto gain adjustment).

1. On and off are alternately switched in the same command.
2. For a stop, select “19 ALL SRV OFF” and press the 

[         AMS         ]

dial.

The communication between microcomputer and main ICs is
checked.

Checking Method:
1. After setting the test mode, rotate the 

[        AMS        ]

 dial to

select “A0. IC SELF CHECK” and press the 

[        AMS        ]

dial to enter.

2. A checking will start automatically. (Checking time is about 3

seconds)

3. At successful completion of check, “IC CHECK OK” is dis-

played. In this case, no error exists in the IC interface.

The check mentioned above tests the communication from micro-
computer to main ICs. Even if the check successfully finished, the
IC to be checked is not always normal. Consider it for reference
only.

4. In case of an IC communication error, the following display

will be given during the checking. Possible causes of error are
as listed below.

Error display

Causes  (typical example)

DVD DEC. ERROR

1. IC701 (SACD decoder) is faulty
2. IC701 pin <znv (XRST) does not go “H”

• IC901 pin ts (XDIS IO) does not go “H”
• IC904 (PLD) is faulty

3. 768fs (33.8688 MHz) is not present to

IC701 pin <znm (XTAL)

• IC811 (3-multiplying circuit) is faulty
• Clock signal 256fs is not sent from

AUDIO board (CN701 pin qg)

• CN702 pin 6 (GND) and pin 7

(+3.3V-D) are open or shorted

• CN701, 702 and FFC connection is loose,

or FFC is disconnected

DVD DRAM ERR

1. IC706 (D-RAM) is faulty
2. IC701 pin <znv (XRST) does not go “H”

• IC901 pin ts (XDIS IO) does not go “H”
• IC904 (PLD) is faulty

3. Faulty communication line between

IC701 and IC706
• Data line, address line, WE, etc.

4. D903 (1SS367) is faulty

D+3.3V is not present to IC706

CD DSP ERROR

1. IC509 (CD DSP) is faulty
2. 768fs (33.8688 MHz) is not present to

IC509 pin ua (XTAL)

Same as cause 3 of DVD DEC. ERROR

3. IC509 pin 2 (XRST) does not go “H”

• IC901 pin ts (XDIS IO) does not go “H”
• IC904 (PLD) is faulty

Error display

Causes  (typical example)

EEPROM ERROR

1. IC903 (EEPROM) is faulty

SAMBA DRAM ERR

1. IC808 (D-RAM) is faulty

(DSD decoder is also

2. IC801 (DSD decoder) is faulty

checked)

3. 768fs (33.8688 MHz) is not present to

IC801 pin qa (MCKI)

Same as cause 3 of DVD DEC. ERROR

4. IC801 pin 9 (XRST) does not go “H”

• IC901 pin ts (XDIS IO) does not go “H”
• IC904 (PLD) is faulty

5. Faulty communication line between

IC801 and IC808
• Data line, address line, WE, etc.

6. D904 (1SS367) is faulty

D+3.3V is not present to IC808

RF AMP ERROR

1. IC001 (RF AMP) is faulty
2. Loose connection between CN708 on

MAIN board and CN005 on RF board,
or FFC disconnection
CN708 pin qj  (CLK RF), pin qh  (DATA

RF) and pin qg (SDEN) must be checked

SD BUS ERROR

1. IC701 SD bus and IC801 AV decoder

interface is faulty

2. IC812 to 814 are faulty

Causes Common to Each IC:
1. Faulty communication line between microcomputer and each

IC.
Disconnected patterns, floating series resistors, bridge, etc.

2. Faulty IC supply voltage.

Particularly, check D+3.3V voltage.

3. Faulty microcomputer communication port to each IC

In case of more than two errors, the error display is switched over
one after another, thus making the reading difficult.
In such a case, press again the 

[        AMS        ]

 dial to make a

recheck for error reading.

Checking Method:
1. After setting the test mode, rotate the 

[        AMS        ]

 dial to

select “8A. FL CHECK” and press the 

[        AMS        ]

 dial to

enter.

2. Respective segments of fluorescent indicator tube will

automatically light up in order, and therefore check that there
is no chipped character.

3. The “INPUT REMOCON” will be displayed after the segment

check finished successfully, and then press a proper key on
the remote commander.

4. After “JOG CHECK” is displayed, the numbers of calendar

will be displayed from 1 to 15 each time the 

[        AMS        ]

dial is rotated clockwise.

5. After display up to 15, the numbers of calendar will

disappear in order each time the 

[         AMS         ]

 dial is

rotated counterclockwise.

6. “TTX-1514?” will be displayed when all are cleared, and then

press the 

[        AMS        ]

 dial.

7. Upon display of “KEY CHECK”, if a key on the display is

pressed, the corresponding segment of fluorescent indicator
tube will light up.

8. “FL TEST END” will be displayed if all keys are pressed.

Note: The keys include the 

[        AMS        ]

 dial. If the segment that

corresponds to the pressed key does not light up, that key is faulty.

9. The test mode selection display will be back, if the 

[         AMS         ]

dial is pressed.

l

L

l

L

l

L

l

L

l

L

l

L

l

L

l

L

l

L

l

L

l

L

l

L

l

L

15

The operational stability of the set is checked. The check and OK/NG judgment are performed automatically.

: In the set check using the CD, besides a checking, the MIRR time used for the disc check is measured every optical pick-up, and from the measured

result, the threshold value is calculated and it is stored in the EEPROM (IC903) on the MAIN board. Accordingly, if a combination of optical pick-
up and EEPROM is changed (for example, the optical pick-up or MAIN board is replaced), be sure to perform the set check using the following CD.
As the data stored in the EEPROM are overwritten every set check, retry if failed. For the set check using the SACD, only checking is made.

Checking method:
1. After setting the test mode, rotate the 

[        AMS        ]

 dial to select “SET CHECK” and press the 

[        AMS        ]

 dial to enter.

2. Upon display of “AUTO CHECK SP?”, further press the 

[        AMS        ]

 dial.

3. The tray will open automatically, and then set the test disc*1 of CD or SACD.
4. With the “DISC IN&JOG ON” displayed, press the 

[        AMS        ]

 dial, and the check will be executed automatically.

5. “SPEC OK!” will be displayed if the measured result is within the specification. Faulty item name and the measured result will be

displayed if any measured item is NG.

6. After that, “AUTO CHECK SP?” will be again displayed, and then rotate the 

[        AMS        ]

 dial to select “CHECK END?”. Further,

press the 

[        AMS        ]

 dial, and the test mode selection display will be back, and then press the 

[OPEN/CLOSE    ]

 button and take

the test disc out.

*1 Use PATD-012 or YEDS-18 for CD, and SATD-S5 or SATD-S4 for SACD (SL). Using another disc will result in a checking failure.

Items

Description

Remarks

Offset values before RF (PI), VC, FE, TE signal offset adjustment

At offset 0

RF/VC/FE/TE (ORG)

RF (8 bit data in hex notation)

RF: A0h

VC, FE, TE (9 bit data in hex notation)

VC, FE, TE: 00h

Offset values after RF (PI), VC, FE, TE signal offset adjustment

VC offset is not adjusted

RF/VC/FE/TE (ADJ)

(Less than ORG value if offset correction is normal)

(Measurement only)

RF (8 bit data in hex notation)

Also, for SACD, the TE offset is

VC, FE, TE (9 bit data in hex notation)

not measured and adjusted

PI (ORG): PI value at disc type check (decimal data)

PI level conversion

PI (ADJ): PI value after PI offset adjustment

Read value 

× 12.9mV

(read value at microcomputer A/D) (decimal data)

PI/TRVS PP (ORG/ADJ)

TRVS PP (ORG): Traverse level before level correction (AGC)

Traverse level conversion

(decimal data)

Read value 

× 12.9mV

TRVS PP (ADJ):Traverse level after level correction (AGC)

(decimal data)

12.9mV=3.3V 

÷ 256 (8 bit)

PIOR: Set value of PI offset coarse adjusting register

Registers in RF amplifier

PIOR/CCR/TRCR

CCR: Set value of FE offset coarse adjusting register
TRCR: Set value of TE offset coarse adjusting register

FOCUS/TRK GAIN

Auto gain adjusted values of focus and tracking servos
(8 bit data in hex notation)

FBIAS: Focus bias set value (9 bit data in hex notation)

TRCR2 adjusts the E-F gain

TRVSC: Traverse center value (9 bit data in hex notation)

balance and used for CD only

FBIAS/TRVSC/TRCR2/CFR

TRCR2: Set value of E-F balance coarse adjusting register

(Fixed to 06 for SACD)

CFR: Set value of traverse level adjusting register

TRCR2 and CFR are registers in
RF amplifier

PSP AMPLITUDE

SACD only

1-LAST TRK SEEK (msec)

Average seek time from first track to last track of disc

Error rate measurement

For the CD, Measure for 7 sec at track

ERROR RATE

For CD: Average value/Maximum value of C1 and C2

No.5

For SACD: Average value/Maximum value of PO, PI1 and PI2

For the SACD, calculation from 100-
block data at track No.5

l

L

A

The set check is executed to judge OK or NG.
(For the CD, the threshold value is stored in the EEPROM)

The measured result is displayed on the fluorescent indicator tube.

The set check of measurement only is executed.

The measured result is displayed via RS-232C.

The set check is finished.

l

L

l

L

l

L

l

L

l

L

16

Measured Items

Specified value

RF AVRG (ADJ)

8Ch to ABh

VC AVRG (ADJ)

1F7h to09h

FE  AVRG (ADJ)

(1) CD

1EEh to 12h

(2) SACD

1F1h to 0Fh

TE AVRG (ADJ)

1E2h to 1Eh

TRVS PP (ADJ)

45h to 73h

FCS GAIN

10h to 60h

TRK GAIN

10h to 60h

(1) CD

C1

20 or less

ERROR RATE

C2

0

(2) SACD

PI1 NUM

100 or less

PI1 FRAME

5 or less

PSP AMPLITUDE (SACD only)

1000 to 4000

1-LAST TRK SEK

3500 or less

Specified Value:
Specified value used for OK/NG judgment when executing 92. SET CHECK

tAUTO CHECK SP?

 The specified values attached with “h” are hexadecimal numbers, and others are decimal numbers.

RF, VC, FE, and TE measured values are hexadecimal data with positive and negative signs. When comparing the measured
value with the specified value, refer to the following.