Sony Vx8 Owners Manual

Ð 11 Ð
AMS Test  Mode
¥ This mode is used for checking the AMS operations of the tape deck.
JIG
7-819-039-12 Alignment  tape, AMS-110A
Procedure:
1. Press the  1/u  button to turn the unit ON.
2. Set the tape (AMS-110A).
3. Press the three buttons  p  ,  ENTER/NEXT  , and  DISC 3  button simultaneously.
4. ÒTEST MODEÓ is displayed on the fluorescent display tube.
5. Press the  FUNCTION  button and switch the function to the deck with the tape (AMS-110A).
6. Press the  CD SYNC  button. ÒAMS CHECKÓ is...

Ð 12 Ð
SECTION  5
TEST MODE
VIDEO CD COLOR-BARS MODE
On this mode, the data of the color-bars signal as a picture signal and the 1kHz sine wave signal as a sound signal are output by the
mechanism control microcomputer (IC502) for video CD signal check. When measurement of the voltage and waveform on the VIDEO
board, perform it in this mode.
For refernce, the color-bars signal can be observed at J302 (VIDEO OUT) and the sound signal can be observed at J101 (VIDEO/MD
(AUDIO) OUT) using an oscilloscope.
1....

Ð 13 Ð
Precaution
1. Clean the following parts with a denatured alcohol-moistened
swab:
record/playback heads pinch rollers
erase head rubber belts
capstan idlers
2. Demagnetize the record/playback head with a head demagne-
tizer.
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the rated power sup-
ply voltage unless otherwise noted.
Torque Measurement
31 to 71 g ¥ cm...

Ð 14 Ð
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
Adjustment Location:Playback Head (Deck A)
Record/Playback/Erase Head (Deck B) 3. Mode: PlaybackTape Speed Adjustment (Deck A)
Note:Set the test mode using the following method and begin tape
speed adjustment.
In the test mode, the speed will switch to double speed or
normal speed each time the  HI DUB  button is pressed.
Procedure:
With the power turned ON, press the p  button,  ENTER/NEXT
button, and  DISC 3  button...

Ð 15 Ð
Record Bias Adjustment  (Deck B)
Procedure:
INTRODUCTION
When set to the test mode performed in Tape Speed Adjust-
ment, when the tape is rewound after recording, the ÒREC memory
modeÓ which rewinds only the recorded portion and playback is
set.
This ÒREC memory modeÓ is convenient for performing this ad-
justment. During recording, the input signal FUNCTION will auto-
matically switch to VIDEO.
(After recording, press the  Ð 0  button without stopping will
return to the position where recording...

Ð 16 Ð
CD SECTION
Note:
1. CD Block is basically constructed to operate without adjustment.
Therefore, check each item in order given.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10MW impedance.
4. Clean the object lens by an applicator with neutral detergent when
the signal level is low than specified value with the following
checks.
S Curve Check
Adjustment Location: BD board
Procedure :
1. Connect the oscilloscope to test points TP (FE) and TP...

Ð 17 Ð
VIDEO SECTION
Frequency adjustment
1. Connect the frequency counter to check point of the VIDEO
board.
2. Adjust CT503 of the VIDEO board so that the frequency counter
read 27MHz ± 80Hz at STOP condition.
[ VIDEO BOARD ] Ð SIDE B Ð Adjustment Location :
[ VIDEO BOARD ] Ð SIDE A Ðfrequency counter
VIDEO board
(29 MHz)+
–
SL501IC502IC506 (27MHz)
(GND)
SL502 SL503
TEST
MODE
SL501 D502
SL502
CT503 SL503TEST MODE
VIDEO
FREQUENCY
(27MHz)
(GND)IC507 IC505
Adjustment Location :
[ BD BOARD ] Ñ SIDE B Ñ
TP...

Ð 18 Ð
SECTION  8
DIAGRAMS
8-1. CIRCUIT BOARDS LOCATION
ENCAPSULATED COMPONENT/TUNER
unit is supplied as the assembled block.
MAIN board PANEL board
CD SW board
SURROUND board
ENCAPSULATED COMPONENT
(EXCEPT THAI)
TUNER unit
(THAI)
TRANS board
VIDEO board
SENSOR boardCONNECTOR board
BD board
MOTOR (SLIDE) board MOTOR (TURN) board
AUDIO board LEAF SW board 

HCD-VX8/VX8J
Ð 19 ÐÐ 20 Ð
8-2. BLOCK DIAGRAMS
Ð CD SECTION Ð
E
FA
BC
D
DRIVE
Q101LDRF EQ 
AMP
SUMMING
AMPRFERROR
AMP FOCUSERROR
AMP TRACKING
APC LD 
AMP
VC 
BUFFER
VC 
REF  RF AMPIC103DIGITAL SERVO
DIGITAL SIGNAL PRCESSORIC101IC381
LASER
DIODE DETECTOR OPTICAL PICK-UP BLOCK
(D/Q-Np)
A
C
D
B
E
F
LD
POWERPDLD
PDLDA
C
D
B
E
FTE  FE RFD 
RFI
ASYMMETRY 
CORRECTION
AUTO
SEQUENCERSERVO
INTEG- 
RATOR
DIGITAL 
PLL
EFM 
DEMODULATOR
 
REGISTER
SUB CODE
PROCESSOR
ERROR
CORRECTOR
DATA BUS
32K 
RAM
D/A
INTERFACE...

HCD-VX8/VX8JÐ VIDEO SECTION Ð
Ð 21 ÐÐ 22 Ð
SYSTEM
SELECTS501
651513
09
29
     I
2C.CLK
30
     I
2C.DATA I
2C.CLK   I2C.DATA
 I to U
 U to I
 TXD
 RXD
72
     U to I      DSENS      XRESET      TEST LED     NT/PAL     XOUT
     +5V
     D502      A7      DF LATCH      SHARPNESS
     XIN
24
45
BUS
DSP DATA
DSP LATCH
SENSE CLKDSP CLK
SENSE
DSP MUTE
CTRL1(L:DOUBLE)
CTRL2
LDON
SCOR
SUBQ DATA
2234
X501
NTSC
AUTO
PAL   10MHz
X503
27MHz
1920X401
8MHz MECHA. CONTROL
IC502
INTERFACE
IC402LEVEL SHIFT
IC504 LEVEL...