Hitachi VT-FX685A Service Manual
TK No. 5102E
VT-FX685A
SERVICE MANUAL
PLAY
STOP/EJECT
REW F.FWD
REC/IRT
VIDEO-IN
AUDIO-INL R
POWER
CHANNEL
TRACKING
VT-FX685AC
CONTENTS
MAIN SECTION
Specifications .......................................................1- 1 -1
Important Safety Precautions ..............................1- 2 -1
Standard Notes for Servicing ...............................1- 3 -1
Preparation for Servicing .....................................1- 4 -1
Operating Controls and Functions .......................1- 5 -1
Cabinet Disassembly Instructions .......................1- 6 -1
Electrical Adjustment Instructions .......................1- 7 -1
Block Diagrams ....................................................1- 8 -1
Function Indicator Symbols ................................ 1- 8 -11
SchematicDiagrams / CBA' s and Test Points ...1- 9 -1
Waveforms ...........................................................1- 9 -8
Wiring Diagram ................................................1-10-1
System Control Timing Charts ..............................1-11-1
IC Pin Function .....................................................1-12-1
Lead Identifications ...............................................1-13-1
This video deck is VHS type video
recorder. For proper operation, only
the VHS type cassette must be
used.
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
VIDEO CASSETTE RECORDER
DECK MECHANISM SECTION
Standard Maintenance ......................................... 2- 1 -1
Fixture and Tape for Adjustment ......................... 2- 2 -1
Mechanical Alignment Procedures ...................... 2- 3 -1
Disassembly / Assembly Procedures of
Deck Mechanism ..... 2- 4 -1
Alignment Procedures of Mechanism .................. 2- 4 -9
EXPLODED VIEWS AND PARTS LIST SECTION
Exploded Views ................................................... 3- 1 -1
Mechanical Parts List ........................................... 3- 2 -1
Electrical Parts List .............................................. 3- 3 -1
May 2001
Digital Media Products Division, Tokai
MAIN SECTION
VIDEO CASSETTE RECORDER
VT-FX685A
VT-FX685AC
MAIN SECTION
● Specifications
● Preparation for Servicing
● Adjustment Procedures
● Schematic Diagrams
● CBA’ s
TABLE OF CONTENTS
Specifications.................................................................................................................................................... 1- 1 -1
Important Safety Precautions............................................................................................................................ 1- 2 -1
Standard Notes for Servicing............................................................................................................................ 1- 3 -1
Preparation for Servicing .................................................................................................................................. 1- 4 -1
Operating Controls and Functions .................................................................................................................... 1- 5 -1
Cabinet Disassembly Instructions..................................................................................................................... 1- 6 -1
Electrical Adjustment Instructions..................................................................................................................... 1- 7 -1
Block Diagrams................................................................................................................................................. 1- 8 -1
Function Indicator Symbols..............................................................................................................................1- 8 -11
Schematic Diagrams / CBA’ s and Test Points ................................................................................................. 1- 9 -1
Waveforms........................................................................................................................................................ 1- 9 -8
Wiring Diagram ................................................................................................................................................. 1-10-1
System Control Timing Charts .......................................................................................................................... 1-11-1
IC Pin Function ................................................................................................................................................ 1-12-1
Lead Identifications........................................................................................................................................... 1-13-1
SPECIFICATIONS
Description Unit Minimum Nominal Maximum Condition
1. Video
1-1 Video Output (PB) Vp-p 0.8 1.0 1.2
1-2 Video Output (R/P) Vp-p 0.8 1.0 1.2
1-3 Video S/N Y (R/P) dB 41 44 SP Mode
1-4 Video Color S/N AM (R/P) dB 35 44 SP Mode
1-5 Video Color S/N PM (R/P) dB 33 37 SP Mode
1-6 Resolution (PB) Line 210 230 SP Mode
2. Servo
2-1 Jitter Low (R/P) µs 0.05 0.1 SP Mode
2-2 Wow & Flutter (R/P) % 0.2 0.4 SP Mode
3. Normal Audio
3-1 Output (PB) dBV -10 -6 -2
3-2 Output (R/P) dBV -10 -6 -2 SP Mode
3-3 S/N (R/P) dB 38 43 SP Mode
3-4 Distortion (R/P) % 2 4.0 SP Mode
3-5 Freq. response (R/P) at 200Hz dB -6 0 SP Mode
(-20dB ref. 1kHz) at 8kHz dB -6 -1.5 SP Mode
4. Tuner
4-1 Video Output Vp-p 0.8 1.0 1.2 E-E Mode
4-2 Video S/N (S/N Y signal) dB 40 47 E-E Mode
4-3 Audio Output (1kHz) dBV -10 -6 -4 E-E Mode
4-4 Audio S/N (1kHz) dB 40 46 E-E Mode
Note: Nominal specs represent the design specs. All units should be able to approximate these – some will exceed
and some may drop slightly below these specs. Limit specs represent the absolute worst condition that still might be
considered acceptable; In no case should a unit fail to meet limit specs.
1-1-1
IMPORTANT SAFETY PRECAUTIONS
Product Safety Notice
Some electrical and mechanical parts have special
safety-related characteristics which are often not evident from visual inspection, nor can the protection they
give necessarily be obtained by replacing them with
components rated for higher voltage, wattage, etc. Parts
that have special safety characteristics are identified by
a # on schematics and in parts lists. Use of a substitute replacement that does not have the same safety
characteristics as the recommended replacement part
might create shock, fire, and/or other hazards. The
Product’s Safety is under review continuously and new
instructions are issued whenever appropriate. Prior to
shipment from the factory, our products are carefully
inspected to confirm with the recognized product safety
and electrical codes of the countries in which they are
to be sold. However, in order to maintain such compliance, it is equally important to implement the following
precautions when a set is being serviced.
Precautions during Servicing
A.Parts identified by the # symbol are critical for
safety. Replace only with part number specified.
B.In addition to safety, other parts and assemblies are
specified for conformance with regulations applying
to spurious radiation. These must also be replaced
only with specified replacements.
Examples: RF converters, RF cables, noise blocking capacitors, and noise blocking filters, etc.
C.Use specified internal wiring. Note especially:
1) Wires covered with PVC tubing
2) Double insulated wires
3) High voltage leads
D.Use specified insulating materials for hazardous live
parts. Note especially:
1) Insulation tape
2) PVC tubing
3) Spacers
4) Insulators for transistors
E.When replacing AC primary side components
(transformers, power cord, etc.), wrap ends of wires
securely about the terminals before soldering.
F. Observe that the wires do not contact heat produc-
ing parts (heatsinks, oxide metal film resistors, fusible resistors, etc.).
G.Check that replaced wires do not contact sharp
edges or pointed parts.
H.When a power cord has been replaced, check that
5 - 6 kg of force in any direction will not loosen it.
I.Also check areas surrounding repaired locations.
J.Use care that foreign objects (screws, solder drop-
lets, etc.) do not remain inside the set.
K.Crimp type wire connector
The power transformer uses crimp type connectors
which connect the power cord and the primary side
of the transformer. When replacing the transformer,
follow these steps carefully and precisely to prevent
shock hazards.
Replacement procedure
1)Remove the old connector by cutting the wires at a
point close to the connector.
Important: Do not re-use a connector. (Discard it.)
2)Strip about 15 mm of the insulation from the ends of
the wires. If the wires are stranded, twist the strands
to avoid frayed conductors.
3)Align the lengths of the wires to be connected. Insert
the wires fully into the connector.
4)Use a crimping tool to crimp the metal sleeve at its
center. Be sure to crimp fully to the complete closure
of the tool.
L.When connecting or disconnecting the internal con-
nectors, first, disconnect the AC plug from the AC
outlet.
1-2-1
Safety Check after Servicing
Examine the area surrounding the repaired location for
damage or deterioration. Observe that screws, parts,
and wires have been returned to their original positions.
Afterwards, do the following tests and confirm the specified values to verify compliance with safety standards.
1. Clearance Distance
When replacing primary circuit components, confirm
specified clearance distance (d) and (d’) between soldered terminals, and between terminals and surrounding metallic parts. (See Fig. 1)
Table 1 : Ratings for selected area
AC Line Voltage Clearance Distance (d) (d’)
120 V ≥ 3.2 mm (0.126 inches)
Note: This table is unofficial and for reference only.
Be sure to confirm the precise values.
2. Leakage Current Test
Confirm the specified (or lower) leakage current between B (earth ground, power cord plug prongs) and
externally exposed accessible parts (RF terminals, antenna terminals, video and audio input and output terminals, microphone jacks, earphone jacks, etc.) is lower
than or equal to the specified value in the table below.
Measuring Method (Power ON) :
Insert load Z between B (earth ground, power cord plug
prongs) and exposed accessible parts. Use an AC
voltmeter to measure across the terminals of load Z.
See Fig. 2 and the following table.
Z
1.5kΩ
Chassis or Secondary Conductor
Primary Circuit Terminals
dd'
Exposed Accessible Part
AC Voltmeter
0.15µF
Earth Ground
B
Power Cord Plug Prongs
(High Impedance)
Fig. 1
Fig. 2
Table 2 : Leakage current ratings for selected areas
AC Line Voltage Load Z Leakage Current (i) Earth Ground (B) to:
120 V
Note: This table is unofficial and for reference only. Be sure to confirm the precise values.
0.15µF CAP. & 1.5kΩ RES.
Connected in parallel
i ≤ 0.5mA Peak Exposed accessible parts
1-2-2
STANDARD NOTES FOR SERVICING
Circuit Board Indications
a.The output pin of the 3 pin Regulator ICs is indicated
as shown.
Top View
Out
b.For other ICs, pin 1 and every fifth pin are indicated
as shown.
Input
In
Bottom View
5
Pin 1
10
c.The 1st pin of every male connector is indicated as
shown.
Pin 1
Instructions for Connectors
1.When you connect or disconnect the FFC (Flexible
Foil Connector) cable, be sure to first disconnect the
AC cord.
2.FFC (Flexible Foil Connector) cable should be inserted parallel into the connector, not at an angle.
How to Remove / Install Flat Pack-IC
1. Removal
With Hot-Air Flat Pack-IC Desoldering Machine:
(1)Prepare the hot-air flat pack-IC desoldering ma-
chine, then apply hot air to the Flat Pack-IC (about
5 to 6 seconds). (Fig. S-1-1)
Fig. S-1-1
(2)Remove the flat pack-IC with tweezers while apply-
ing the hot air.
(3)Bottom of the flat pack-IC is fixed with glue to the
CBA; when removing entire flat pack-IC, first apply
soldering iron to center of the flat pack-IC and heat
up. Then remove (glue will be melted). (Fig. S-1-6)
(4)Release the flat pack-IC from the CBA using tweez-
ers. (Fig. S-1-6)
Caution:
1.Do not supply hot air to the chip parts around the flat
pack-IC for over 6 seconds because damage to the
chip parts may occur. Put masking tape around the
flat pack-IC to protect other parts from damage.
(Fig. S-1-2)
2.The flat pack-IC on the CBA is affixed with glue, so
be careful not to break or damage the foil of each
pin or the solder lands under the IC when removing
it.
FFC Cable
Connector
CBA
* Be careful to avoid a short circuit.
1-3-1
CBA
Masking
Tape
Tweezers
Hot-air
Flat Pack-IC
Desoldering
Machine
Flat Pack-IC
Fig. S-1-2
With Soldering Iron:
(1)Using desoldering braid, remove the solder from all
pins of the flat pack-IC. When you use solder flux
which is applied to all pins of the flat pack-IC, you
can remove it easily. (Fig. S-1-3)
(4)Bottom of the flat pack-IC is fixed with glue to the
CBA; when removing entire flat pack-IC, first apply
soldering iron to center of the flat pack-IC and heat
up. Then remove (glue will be melted). (Fig. S-1-6)
(5)Release the flat pack-IC from the CBA using tweez-
ers. (Fig. S-1-6)
Flat Pack-IC
Desoldering Braid
Soldering Iron
Fig. S-1-3
(2)Lift each lead of the flat pack-IC upward one by one,
using a sharp pin or wire to which solder will not
adhere (iron wire). When heating the pins, use a fine
tip soldering iron or a hot air desoldering machine.
(Fig. S-1-4)
Sharp
Pin
Note:
When using a soldering iron, care must be taken to
ensure that the flat pack-IC is not being held by glue.
When the flat pack-IC is removed from the CBA,
handle it gently because it may be damaged if force
is applied.
Hot Air Blower
or
Iron Wire
Soldering Iron
To Solid
Mounting Point
Fig. S-1-5
Fine Tip
Fig. S-1-4
Soldering Iron
(3)Bottom of the flat pack-IC is fixed with glue to the
CBA; when removing entire flat pack-IC, first apply
soldering iron to center of the flat pack-IC and heat
up. Then remove (glue will be melted). (Fig. S-1-6)
(4)Release the flat pack-IC from the CBA using tweez-
ers. (Fig. S-1-6)
With Iron Wire:
(1)Using desoldering braid, remove the solder from all
pins of the flat pack-IC. When you use solder flux
which is applied to all pins of the flat pack-IC, you
can remove it easily. (Fig. S-1-3)
(2) Affix the wire to a workbench or solid mounting point,
as shown in Fig. S-1-5.
(3)While heating the pins using a fine tip soldering iron
or hot air blower, pull up the wire as the solder melts
so as to lift the IC leads from the CBA contact pads
as shown in Fig. S-1-5.
CBA
Tweezers
Fine Tip
Soldeing Iron
Flat Pack-IC
Fig. S-1-6
1-3-2
2. Installation
(1)Using desoldering braid, remove the solder from the
foil of each pin of the flat pack-IC on the CBA so you
can install a replacement flat pack-IC more easily.
(2)The " ● " mark on the flat pack-IC indicates pin 1.
(See Fig. S-1-7.) Be sure this mark matches the 1
on the PCB when positioning for installation. Then
pre- solder the four corners of the flat pack-IC. (See
Fig. S-1-8.)
(3)Solder all pins of the flat pack-IC. Be sure that none
of the pins have solder bridges.
Example :
Pin 1 of the Flat Pack-IC
is indicated by a " ● " mark.
Fig. S-1-7
Instructions for Handling Semiconductors
Electrostatic breakdown of the semiconductors may
occur due to a potential difference caused by electrostatic charge during unpacking or repair work.
1. Ground for Human Body
Be sure to wear a grounding band (1MΩ) that is properly
grounded to remove any static electricity that may be
charged on the body.
2. Ground for Workbench
Be sure to place a conductive sheet or copper plate with
proper grounding (1MΩ) on the workbench or other
surface, where the semiconductors are to be placed.
Because the static electricity charge on clothing will not
escape through the body grounding band, be careful to
avoid contacting semiconductors with your clothing.
< Incorrect >
CBA
Presolder
Flat Pack-IC
CBA
< Correct >
Grounding Band
Fig. S-1-8
1MΩ
CBA
1MΩ
Conductive Sheet or
Copper Plate
1-3-3
PREPARATION FOR SERVICING
How to Enter the Service Mode
About Optical Sensors
Caution:
An optical sensor system is used for the Tape Start and
End Sensors on this equipment. Carefully read and
follow the instructions below. Otherwise the unit may
operate erratically.
What to do for preparation
Insert a tape into the Deck Mechanism Assembly and
press the PLAY button. The tape will be loaded into the
Deck Mechanism Assembly. Make sure the power is
on, connect TP502 (SENSOR INHIBITION) to TP511
(GROUND). This will stop the function of Tape Start
Sensor, Tape End Sensor and Reel Sensors. (If these
TPs are connected before plugging in the unit, the
function of the sensors will stay valid.) See Fig. 1.
Note: Because the Tape End Sensors are inactive, do
not run a tape all the way to the start or the end of the
tape to avoid tape damage.
About REC-Safety Switch
Caution:
The REC-Safety Switch is directly mounted on the Main
CBA. When the Deck Mechanism Assembly is removed
from the Main CBA for servicing, this switch does not
work automatically.
What to do for preparation
In order to record, press the Rec button while pushing
REC-SAFETY SW on the Main CBA. See Fig. 1.
CN501
Q503
CN251
SW506
(REC-SAFETY SW)
CN504
TP511
GND
CN502
CN503
Q504
TP502
S-INH
Fig. 1
1-4-1
OPERATING CONTROLS AND FUNCTIONS
Model: VT-FX685A / VT-FX685AC
VCR FRONT PANEL
AUDIO-INLR
VIDEO-IN
27
30
VCR REAR PANEL
25
25
1
POWER
6
CHANNEL
TRACKING
91087
26
26
AUDIO
OUT
VIDEO
OUT
OUT IN
OUT IN
29 30 3231
29 30 3231
2 3 4 5
REC/IRT
27
L
IN
R
AUDIO
L
CH3 CH4
IN
R
VIDEO
CH3 CH4
1.Cassette Compartment
2.REW button– Press to rewind the tape, or to view
the picture rapidly in reverse during the playback
mode. (Rewind Search)
s
button– Press to cancel a setting of timer pro-
gram. Press to correct digits when setting program
(For example: setting clock or timer program). Press
to add or delete channel numbers during channel
preset. (only on the remote control)
3. STOP button– Press to stop the tape motion.
EJECT button– Press to remove a tape from the
VCR. (only on the VCR)
▼ button– Press to enter digits when setting pro-
gram (For example: setting clock or timer program).
Press to select the setting modes from the on screen
menu. (only on the remote control)
4.PLAY button– Press to begin playback.
▲ button– Press to enter digits when setting pro-
gram (For example: setting clock or timer program).
Press to select the setting modes from the on screen
menu. (only on the remote control)
5.F.FWD button– Press to rapidly advance the tape,
or view the picture rapidly in forward during playback. (Forward Search)
B button– When setting program (For example:
setting clock or timer program), press to determine
your selection and proceed to the next step you want
to input. Press to determine the setting modes from
the on screen menu. Press to add or delete channel
numbers during channel preset. (only on the remote
control)
27
STOP/EJECT
ANT
REW F.FWD
28
28
IN
ANT
OUT
IN
OUT
REMOTE CONTROL
PLAY
POWER
6
123
11
12
13
456
789
TAPE SPEED
DISPLAYMENU
14
2
3
10
24
REW
REC
VCR PIus+
0
PLAY
STOP
CATV
TVVCR
VCR/TV
CH
ENTER
+100
MUTE
VOL
F.FWD
PAUSE
SLOW
SEARCH MODE
EXIT COUNTER
RESET
MEMORY
6.POWER button– Press to turn VCR on and off.
Press to activate timer recording.
7.Remote sensor window– Receives the infrared
signals from the remote control.
8.Digital display
A
B
C
D
E
F
A.PWR. (Power) indicator– Indicates that the power
is turned on.
B.Cassette indicator– Indicates that there is a tape
in the VCR.
C.VCR indicator– Indicates that the VCR is in the
VCR position.
D.REC indicator– Indicates that it is recording.
Flashes when a recording has been paused.
E.w (Timer) indicator– Indicates that the timer recording
or an IRT recording has been set.
F. CLOCK indicator– Displays current time. PM indi-
cator appears when p.m.
9.CHANNEL(CH) ▲ / ▼ buttons– Press to select the
desired channels for viewing or recording.
Tracking function– Press to minimize video ‘noise’
(lines or dots on screen) during playback (only on
the VCR) or slow mode.
Press to stabilize the picture in the Still mode when
the picture begins to vibrate vertically.
23
22
9
21
20
4
5
19
18
17
16
15
1-5-1
10.REC button– Press for manual recording.
IRT button– Press to activates Instant Recording
Timer. (only on the VCR)
11.NUMBER buttons– Press to select desired channels for viewing or recording. To select channels
from 1 to 9, first press "0" button then 1 to 9. (only
on the remote control)
+100 button– When selecting cable channels which
are higher than 99, press this button first, then press
the last two digits. (To select channel 125, first press
"+100" button then press "2" and "5"). (only on the
remote control)
ENTER– (only on the remote control)
12.TAPE SPEED button Press to choose the desired
recording speed : SP/SLP. (only on the remote control)
13. MENU button– Press to display the menu on the TV
screen. Press to exit the menu on the TV screen.
(only on the remote control)
14.DISPLAY button– Press to display the current time,
channel number, real time tape counter, and other
information on the TV screen. (only on the remote
control)
Each time you press this button, TV screen will
change as shown. The status display (STOP, PLAY
etc.) and the tape speed display (SP, LP (playback
only), or SLP) will disappear after 5 seconds.
<OFF mode>
<COUNT mode> <CLOCK mode>
Press
once
STOP
SP 0:12:34
Press once
Press
once
STOP
SP
5:40PM
CH 02
15.COUNTER RESET button– Press to reset counter
to 0:00:00. (only on the remote control)
EXIT button– Press to exit the menu on the TV
screen. (only on the remote control)
16.COUNTER MEMORY button– Press to set counter
memory on and off. (only on the remote control)
17.SEARCH MODE button– Press to perform a Time
Search or an Index Search. (only on the remote control)
18. PAUSE button– Press to temporarily stop the tape
during recording or to view a still picture during
playback. (only on the remote control)
Frame Advance function– Press to advance the
picture by one frame at a time during the still mode.
(only on the remote control)
19. SLOW button– Press to start slow motion playback.
(only on the remote control)
20.MUTE button– Press to mute the TV’s sound. Press
it again to resume the sound. (only on the remote
control)
21.VOL(ume) buttons– Press to adjust the desired
TV’s volume level by using either ▲ or ▼ button.
(only on the remote control)
22.VCR/TV button– Press to select TV or VCR mode.
(only on the remote control)
VCR position: to view playback, to monitor video
recordings or watch TV using the VCR tuner.
TV position: to watch TV or to view one program
while recording another.
23.MODE SELECT buttons
(only on the remote control)
CATV button
TV button
VCR button
24.VCR Plus+ button– Press to program the automat-
ic timer recording using the VCR Plus+ system.
(only on the remote control)
25.Power cord– Connect to a standard AC outlet
(120V/60Hz).
26.AUDIO OUT jacks– Connect to the audio input
jacks of your audio equipment or another VCR.
27.AUDIO IN jacks– Connect to the audio output jacks
of your audio equipment or another VCR.
28.ANT. IN terminal– Connect to an antenna, Cable
system or Satellite system.
29.VIDEO OUT jack– Connect to the video input jack
of your video camera or another VCR.
30.VIDEO IN jack– Connect to the video output jack of
your video camera or another VCR.
31.CH3/CH4 selector switch– Use to select a video
output channel (3 or 4) for VCR playback.
32.ANT. OUT terminal– Connects to the antenna input
terminal on your TV.
1-5-2
CABINET DISASSEMBLY INSTRUCTIONS
1. Disassembly Flowchart
This flowchart indicates the disassembly steps to gain
access to item(s) to be serviced. When reassembling,
follow the steps in reverse order. Bend, route, and dress
the cables as they were originally.
[1] Top Case
[2] Front Assembly
[3] Deck Assembly
[4] Cylinder Shield
[5] REC Arm Assembly
[6] Main CBA
[7] Function CBA
Disassembly Method
REMOVAL
ID/
LOC.
No.
[1] Top Case 1 3(S-1) -
[2]
[3]
[4]
[5]
[6] Main CBA 4 *2(L-4) -
[7]
↓
➀
PART
Front
Assembly
Deck
Assembly
Cylinder
Shield
REC Arm
Assembly
Function
CBA
↓
➁
REMOVE/
Fig.
*UNHOOK/UNLOCK/
No.
RELEASE/UNPLUG/
DESOLDER
2 *3(L-1), *4(L-2)
3 6(S-2), Spacer,
*(CN251, CN501,
CN502, CN503,
CN504)
32(S-3)
3 ----------
4 *(L-3), Desolder
↓
➂
↓
➃
Note
-
1, 2
-
-
3
↓
➄
Reference Notes
CAUTION: Locking Tabs (L-1) and (L-2) are fragile. Be
careful not to break them.
1. Remove six Screws (S-2) and the Spacer. Then
slowly lift the Deck Assembly up. Lifting Deck Assembly disconnects five Connectors (CN251,
CN501, CN502, CN503, CN504). (Fig. 3)
2. Before installing the Deck Assembly, be sure to
place the pin of LD-SW on Main CBA as shown in
Fig. 5. Then, install the Deck Assembly while aligning the hole of Cam Gear with the pin of LD-SW, the
shaft of Cam Gear with the hole of LD-SW as shown
in Fig. 5.
3. After removing the Main CBA, desolder from bottom
of the Main CBA as shown in Fig. 4 to remove the
Function CBA.
(S-1)
[1]Top Case
1 : Identification (location) No. of parts in the figures
2 : Name of the part
3 : Figure Number for reference
4 : Identification of parts to be removed, unhooked, un-
locked, released, unplugged, unclamped, or
desoldered.
P=Spring, L=Locking Tab, S=Screw,
CN=Connector
*=Unhook, Unlock, Release, Unplug, or Desolder
e.g. 2(S-2) = two Screws (S-2),
2(L-2) = two Locking Tabs (L-2)
5 :Refer to "Reference Notes."
Fig. 1
1-6-1
(L-2)
(L-2)
(S-2)
(L-1)
(S-3)
Spacer
CN501
[2]Front Assembly
Fig. 2
[4]Cylinder Shield
(S-3)
(S-2)
[3]Deck Assembly
CN504
CN502
Desolder from
bottom
(L-4)
[6]Main C.B.A.
[6]Main C.B.A.
[7]Function C.B.A.
(L-4)
(L-3)
Fig. 4
Pin
SW507
LD-SW
[4]REC Arm
Assembly
CN251
CN503
Fig. 3
1-6-2
[4]Deck Assembly
Shaft
Hole
LD-SW
Cam Gear
Hole
Pin
[6]Main C.B.A.
Fig. 5
ELECTRICAL ADJUSTMENT INSTRUCTIONS
General Note: "CBA" is an abbreviation for
"Circuit Board Assembly."
NOTE:
1.Electrical adjustments are required after replacing
circuit components and certain mechanical parts. It
is important to do these adjustments only after all
repairs and replacements have been completed.
Also, do not attempt these adjustments unless the
proper equipment is available.
2.To perform these alignment / confirmation procedures, make sure that the tracking control is set in
the center position: Press either channel "▼" or "▲"
button first, then the "PLAY" button (VCR’s Front
Panel only).
CH1
CH2
Figure 1
EXT. Syncronize Trigger Point
1.0H
6.5H
Switching Pulse
V-Sync
0.5H
Test Equipment Required
1.Oscilloscope: Dual-trace with 10:1 probe, V-Range:
0.001~50V/Div., F-Range: DC~AC-20MHz
2.Alignment Tape (MH-1)
Head Switching Position Adjustment
Purpose:
To determine the Head Switching point during playback.
Symptom of Misadjustment:
May cause Head Switching noise or vertical jitter in
the picture.
Test Point Adj. Point Mode Input
TP751(V-OUT)
TP302(RF-SW)
TP511(GND)
Tape
MH-1 Oscilloscope
Connections of Measurement Equipment
VR501
(Switching Point)
(MAIN CBA)
Measurement
Equipment
PLAY
(SP)
6.5H±1H
(412.7µs±60µs)
----
Spec.
Reference Notes:
Play back the Alignment tape and adjust VR501 so that
the V-sync front edge of the CH1 video output waveform
is at the 6.5H(412.7µs) delayed position from the rising
edge of the CH2 head switching pulse waveform.
Main CBA
Oscilloscope
TP751
TP511
TP302
CH1 CH2
Trig. (+)
1-7-1
Servo/System Control Block Diagram BLOCK DIAGRAMS
(DECK ASSEMBLY)
AC HEAD ASSEMBLY
CONTROL
HEAD
CYLINDER ASSEMBLY
DRUM
MOTOR
PG
SENSOR
LOADING MOTOR ASSEMBLY
LOADING
MOTOR
CAPSTAN MOTOR
CAPSTAN
MOTOR
M
M
M
CN287
5 8CTL(+)
6 9CTL(-)
AL+15.5V/+12V
FG-GND
MAIN CBA
CN504
CN502
1D-W
2D-V
3D-U
4D-COM
5PG-IN
CN504
1LD-M(+)
2LD-M(-)
CN503
1C-F/R
2P-ON+5V
3
4C-FG
5C-POW-SW
6C-CONT
7
8CM-GND
IC301
TP303
CTL
P-ON+5V
AL+15.5V/+12V
(Y/C PROCESS)
CONTROL
AMP
9 23 19
IC506
(DRUM /LOADING MOTOR DRIVE)
25
24
22
21
15
16
17
4
2
+
-
DRIVE
TP506 TP505
ST-S
Q504
ST-S
18
DRUM
MOTOR
DRIVE
LOADING
MOTOR
CONTROL
Q503
END-S
AL+5V
D555
S-LED
T-REEL
Q506
T-REEL
TIMER+5V
14
20
18
9
SW507
LD-SW
AL+5V
RS501
REMOTE
SENSOR
TP510
LD-SW
PS502
S-REEL
Q501
RESET
VR501
SW-POINT
AL+5V
AL+5V
IC501
(SERVO/SYSTEM CONTROL)
KEY- 1
KEY- 2
REMOCON-IN
1
PB-CTL
54
REC-CTL(-)
20
19
REC-CTL(+)
LD-SW74
D-CONT56
D-FG
52
D-PG
53
LM-
59
FWD/REV
75
ST-S
68
END-S
T-REEL
49
S-REEL
50
34
RESET
C-F/R
48
51
C-FG
C-POW-SW46
C-CONT
55
71
PG-DELAY
I2C-BUS-CLK
I2C-BUS-DATA
Hi-Fi-CLK
Hi-Fi-DATA
Hi-Fi-H-SW
Hi-Fi-CS
Hi-Fi/NOR-IN
ST/SAP-IN
A-MUTE-H
D-REC-H
REC-SW
D-PB-H
INSEL/ST-SL
C-SYNC
D-V SYNC
V-ENV
C-ROTA
RF-SW
TRICK/C-G/APC
SP/LP/SLP
BLUEBACK-ON
H-A-SW
H-A-COMP
P-ON-L
P-DOWN-L
72
73
G1
81
G4 84
a
85
d
88
e
94
f 89
j
93
10
11
12
18
65
67
13
62
25
61
21
33
70
15
17
47
45
66
16
14
60
63
TP502
S-INH
KEY
SWITCH
TP511
GND
9
8
SW506
REC SW
7
CN507 CN651
3 1KEY 2
DRIVE
Q645~Q648
5
6
TU701(TUNER UNIT)
10
11
ST/SAP-MODE
AL+5V
INSEL/ST-SL
TRICK/C-G/APC
BLUEBACK-ON
FUNCTION CBA
KEY SWITCH
FIP502
LED DISPLAY
IC505
(MEMORY)
SDA
SCL
CLOCK
DATA
Hi-Fi-CLK
Hi-Fi-DATA
Hi-Fi-H-SW
Hi-Fi-CS
NORMAL-H
A-MUTE-H
A-MUTE-H
D-REC-H
D-PB-H
D-REC-H
D-PB-H
C-SYNC
D-V SYNC
V-ENV
C-ROTA
RF-SW
SP/LP/SLP
H-A-SW
H-A-COMP
P-ON-L
P-DOWN-L
C-POW-SW
TO Hi-Fi
AUDIO
BLOCK
TO AUDIO
BLOCK
FROM/TO
VIDEO BLOCK
FROM/TO
POWER
SUPPLY
BLOCK
1-8-1 1-8-2
Video Block Diagram
REC VIDEO SIGNAL PB VIDEO SIGNAL MODE: SP/REC
JK751
V-OUT
TU701
VIDEO-IN
VIDEO-OUT
JK752
REAR V-IN
JK753
FRONT V-IN
5
21
WF1
TP751
V-OUT
Q391
BUFFER
IC501
CHARA-OUT
BLUEBACK
OSD-
OSD-
30
IC301
(Y/C PROCESS)
3131
30
TUNER
42
REAR
38
40
FRONT
BLUEBACK
V-AGC
35
6dB
AMP
CHARA
MIX
FBC
R P
Y/C
MIX
MAIN CBA
45 47 49 44
CCD 1H
DELAY
DOC YNR Y/C COMB
CHROMINANCE
SIGNAL PROCESS
Q301
BUFFER
LUMINANCE
SIGNAL PROCESS
FROM/TO
SERVO/SYSTEM
CONTROL BLOCK
(DECK ASSEMBLY)
CYLINDER ASSEMBLY
VIDEO (R)-1 HEAD
VIDEO (L)-1 HEAD
VIDEO (L)-2 HEAD
VIDEO (R)-2 HEAD
INSEL/ST-SL
D-PB-H
D-REC-H
TRICK/C-G/APC
C-SYNC
C-ROTA
D-V SYNC
SP/LP/SLP
BLUEBACK-ON
71
16
REC/EE/PB
D-REC-H
11
TRICK/C-G/APC
73
34
C-ROTA
14
D-V SYNC
39
SP/LP/SLP
59
BLUEBACK-ON
41
SYNC
SEPA
R
P
AGC
AMP
CN251
1
2
3
4
5
6
V(R)-1
V-COM
V(L)-1
V(L)-2
V-COM
V(R)-2
91
90
89
88
85
84
83
82
R
L
SP
EP
L
R
HPF
ENV
DET
74
R
P
TP302
RF-SW
FROM/TO
SERVO/SYSTEM
CONTROL BLOCK
WF2
RF-SW
V-ENV
H-A-SW
H-A-COMP
13
93
15
H-A-COMP
94
TP301
C-PB
WF5
1-8-3 1-8-4
Audio Block Diagram
PB-AUDIO SIGNAL REC-AUDIO SIGNAL Mode : SP/REC
TU701
SIF OUT
AUDIO-IN
JK751
A-OUT (R)
A-OUT (L)
REAR
A-IN (L)
A-IN (R)
A-IN (L)
FRONT
A-IN (R)
JK752
JK754
JK755
(DECK ASSEMBLY)
19
MAIN CBA
SIF
N-A-OUT
WF8
1
TP753
A-OUT(R)
TP754
A-OUT(L)
IC301
(AUDIO PROCESS) 76
4
EQ
AMP
SP/LP-ON
3
1
2
100
ALC
R
MOD-A
A-OUT (R)
A-OUT (L)
A-IN (L)
A-IN (R)
A-IN (L)-F
A-IN (R)-F
N-A-IN
LINE
AMP
P
MUTE
96
TO Hi-Fi AUDIO
BLOCK
AUDIO
HEAD
AUDIO
ERASE
HEAD
FULL
ERASE
HEAD
AC HEAD ASSEMBLY
FE HEAD
CN287
A-PB/REC 4
A-COM 3
AE-H 1
AE-H 2
CN504
7 A-PB/REC
6 A-COM
4 AE-H
5 AE-H/FE-H
CN501
1 FE-H
2 FE-H-GND
Q422
BIAS
OSC
P-ON+5V
Q423 (PB=ON)
Q425
Q424
(PB=ON)
Q421
SWITCHING
D-REC OFF
P-ON+5V
99
AUTO
BIAS
6
7
REC
AMP
D-REC-H
11 12
1-8-5 1-8-6
REC/EE/PB
16
98
D-PB-H
A-MUTE-H
D-REC-H
FROM
SERVO/SYSTEM
CONTROL BLOCK
Hi-Fi Audio Block Diagram
SIF
IC451 (MTS/ SAP/ Hi-Fi AUDIO PROCESS/ Hi-Fi HEAD AMP)
NOISE
DET
57
SIF
DEMOD
SAP
FILTER
STEREO
FILTER
PILOT
DET
SAP
DEMOD
PILOT
CANCEL
L-R
DEMOD
MAIN CBA
ST/SAP
SW
DC
dBX
DEC
MATRIX
SERIAL
DATA
DECODER
RIPPLE
FILTER
REC-AUDIO SIGNALPB-AUDIO SIGNAL Mode : SP/REC
37
38
39
54
P-ON+9V
Hi-Fi-CS
Hi-Fi-DATA
Hi-Fi-CLK
TO SERVO/ SYSTEM
CONTROL BLOCK
TO
AUDIO BLOCK
A-IN(R)
A-IN(R)-F
N-A-OUT
A-IN(L)
A-IN(L)-F
69
71
STEREO
PLL
R-CH
PNR
R-CH
INSEL
6
7
9
NOR
SW
L-CH
INSEL
48 47
13 14
P
R
SW
NOISE
LIM DEV
COMP
VCO
HOLD
PULSE
NOISE
DET
LPF
MATRIX
R-CH BPF
OUTPUT
SELECT
COMP
ALC
BO
DET
MUTE
ENV
DET
MODE
OUT
51
23
80
78
77
40
49
26
ST/SAP-MODE
NORMAL-H
4
2
1
N-A-IN
A-OUT (L)
MOD-A
A-OUT (R)
Hi-Fi-H-SW
A-MUTE-H
TO SERVO/SYSTEM
CONTROL BLOCK
TO AUDIO BLOCK
TO SERVO/SYSTEM
CONTROL BLOCK
CYLINDER
ASSEMBLY
LPF
L-CH BPF
AGC
AGC
DET
31 30
R
L
24
27
CN251
Hi-Fi-A(R) 7
Hi-Fi-COM 8
Hi-Fi-A(L) 9
Hi-Fi
AUDIO
(R) HEAD
Hi-Fi
AUDIO
(L) HEAD
L-CH
PNR
R
P
LIM DEV
SW
NOISE
VCO
COMP
1-8-7 1-8-8
Power Supply Block Diagram
NOTE :
The voltage for parts in hot circuit is measured using
hot GND as a common terminal.
F
A V
AC001
F001
1A 250V
L001
CHOKE
COIL
D001 - D004
BRIDGE
RECTIFIER
F
A V
CAUTION
FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,
REPLACE ONLY WITH THE SAME TYPE FUSE.
ATTENTION : POUR UNE PROTECTION CONTINUE LES RISQES
D'INCELE N'UTILISER QUE DES FUSIBLE DE MEMO TYPE.
RISK OF FIRE
"This symbol means fast operating fuse."
"Ce symbole reprèsente un fusible à fusion rapide."
Q001
-REPLACE FUSE AS MARKED.
T001
2
4
11
12
13
14
Q052
CAUTION !
Fixed voltage power supply circuit is used in this unit.
If Main Fuse (F001) is blown, check to see that all components in the
power supply circuit are not defective before you connect the AC plug to
the AC power supply. Otherwise it may cause some components in the
power supply circuit to fail.
AL+12V
AL+44V
AL+12V
P-ON-L
P-ON+9V
TIMER+5V
AL+5V
P-ON+5V
P-DOWN-L
AL+15.5V/+12V
C-POW-SW
Q055
HOT
Q029
SWITCHING
CONTROL
Q002
7
6
IC001
ERROR
VOLTAGE DET
4
15
Q060
16
17
18
1
23
Q061
Q062
Q056
(SHUNT REGULATOR)
Q031
REG
COLD
1-8-9 1-8-10
MAIN CBA
FUNCTION INDICATOR SYMBOLS
Power Supply Trouble Shooting Guide
Note:
The following symbols will appear on the indicator panel to indicate the current mode or operation of the VCR.
On-Screen modes will also be momentarily displayed on the TV screen when you press the operation buttons.
Display panel
LED MODE INDICATOR ACTIVE
CASSETTE "IN"
CASSETTE "OUT"
VCR/TV VCR MODE
VCR/TV TV MODE
CLOCK " 88:88 "
POWER ON " PWR. " ON
REC " REC " ON
REC PAUSE " REC " Blinks at 0.8Hz interval
T-REC, OTR " " ON
When reel and capstan mechanism is not
functioning correctly
When tape loading mechanism is not functioning correctly
When cassette loading mechanism is not
functioning correctly
When the drum is not working properly " "
S-INH condition All modes Blinks at 0.8Hz interval
" "
" "
" VCR "
" VCR "
" PM "
" "
" 1 "
" "
" 2 "
" "
" 3 "
" 4 "
ON
OFF
ON
OFF
ON
ON/OFF
(T-REC OFF, T-REC incomplete
Blinks at 0.8Hz interval)
Blinks at 0.8Hz interval
Blinks at 0.8Hz interval
Blinks at 0.8Hz interval
Blinks at 0.8Hz interval
It is highly recommended that a variable isolation
transformer which can monitor current be used.
(Alternatively a variable AC source which monitors
current will do). Read directions below before power
is added!
Repair method
CHECK
Connect unit to the isolation transformer and slowly increase the AC supply while monitoring the current, if it
draws too much current (Be ware fuse
is rated for 1.0 amps), then turn off
supply and do repair method #1.
NO
Check whether the primary rectifying
DC of the Switching power supply has
an output. (Reading should be about
168V.)
YES
With the primary DC working check
the secondary 5V.
YES
Are the 40V, 12V, -30V, 5V, 15V and
filaments lines higher than normal?
NO
Although the secondary 5V is working,
are any of the other voltages higher
than normal (40V, 12V, -30V, 15V and
filament voltages)?
NO
There is no problem on the SW power
supply.
YES
NO
NO
YES
YES
#1
#2
#3
#4
#5
Repair method #1
(Power must be off)
Short circuit in the secondary side. check diode D013
and {(FIP display model only: D012, D014, D015, D016
and D017) or (LED display model only: D014, D015 and
D016)}, switching FET (Q001), control transistor
(Q002), diode (D006), and resistor (R014) replace as
necessary.
Disconnect 40V diode (D013), 15V diode (D014), 12V
diode (D015),
5V diode (D016) and {FIP display model only: -30V
diode (D012) and filament voltage diode (D017)}Check
the load continuity of 40V line, 15V line, 12V line, 5V
line, -30V line and filament voltage line through a tester
(resistance range).
If the tester indicates a lower resistance value around 0
ohm, the line is short-circuited.
Before repairing the switching power supply, find out the
short-circuited area of such line and repair it.
If the tester does not indicate any low resistance value
(around 0 ohm), no load is short-circuited and there is
no problem.
2] Check for any defective parts while the secondary
rectifying diodes are disconnected (D013, D014, D015,
D016 and {FIP display model only: D012 and D017)}
perform a diode check in both forward and reverse
directions through a tester.
3] Remove the following components and check for
defects: snubber diode (D051), switching FET (Q001),
source resistor (R014), control transistor (Q002).
Repair method #2
Check the fuse 1.0A (F001), primary rectifying diodes
(D001-D004) as possible problems. Remove the above
mentioned parts and check them. The circuit which turns
on switching FET (Q001) may be regarded as a possible
cause, even if the load at the secondary side is shorted,
it can’t be detected because switching FET (Q001) isn’t
operating. Perform check according to the step 1 and 2
of repair method #1 and check the following parts:
(Remove the part from PCB)
Switching FET (Q001), source resistor (R014), gate
resistor (R008) and start resistor (R004 and R005).
Repair method #3
A circuit to turn on switching FET (Q001) may not work
and this may be regarded as a cause of trouble. Even
if the load at the secondary side is short-circuited, it
cannot be detected because switching FET (Q001)
does not turn on. Therefore, perform check according
to the steps 1] and 2] of the repair method #1 and
execute the under-mentioned parts breakage check.
(Remove the part from PCB.)
switching FET (Q001), source resistor (R014), control
transistor (Q002), gate resistor (R008) and start resistor
(R004 and R005).
Repair method #4
The feedback circuit which is monitored by the output of
voltage may not work and this may be regarded as a
possible cause, remove control transistor Q002 and
check for defects. More over, a photo coupler (IC001)
and transistor (Q031) may be defective, replace any
defective parts with factory originals.
Repair method #5
If the output voltage of the secondary side is slightly
high, the line load may be in the "OPEN" state and this
may be regarded as a cause of trouble. If there is no
output voltage on the secondary side, the rectifying
diodes (D013), (D014), (D015) and {FIP display model
only only: (D012) and (D017)} may be defective.
1-8-11
1-8-12
SCHEMATIC DIAGRAMS / CBA’S AND TEST POINTS
Standard Notes
Warning
Many electrical and mechanical parts in this chassis
have special characteristics. These characteristics
often pass unnoticed and the protection afforded by
them cannot necessarily be obtained by using replacement components rated for higher voltage, wattage, etc.
Replacement parts that have these special safety characteristics are identified in this manual and its supplements; electrical components having such features are
identified by the mark " #" in the schematic diagram
and the parts list. Before replacing any of these components, read the parts list in this manual carefully. The
use of substitute replacement parts that do not have the
same safety characteristics as specified in the parts list
may create shock, fire, or other hazards.
Capacitor Temperature Markings
Mark
Capacity
change rate
(B) ±10% 20°C -25~+85°C
(F) +30 -80% 20°C -25~+85°C
(SR) ±15% 20°C -25~+85°C
(Z) +30 -80% 20°C -10~+70°C
Standard
temperature
Temperature
range
Note:
1.Do not use the part number shown on these drawings for ordering. The correct part number is shown
in the parts list, and may be slightly different or
amended since these drawings were prepared.
2.All voltages are DC voltages unless otherwise specified.
Values in schematic diagrams
The values, dielectric strength ( power capacitance )
and tolerances of the resistors ( excluding variable
resistors ) and capacitors are indicated in the schematic
diagrams using abbreviations.
[ Resistors ]
Item Indication
Value
Power
capacitance
No indication...........................Ω
K............................................kΩ
M..........................................MΩ
No indication............1/4W,1/6W
All capacitances other than the
above are indicated in schematic
diagrams.
Capacitors and transistors are represented by the following symbols.
CBA Symbols
(Top View) (Bottom View)
(Bottom View)
E C B
(Top View)
E C B
(Top View)
E C B
Schematic Diagram Symbols
+
Electrolytic Capacitor
Transistor or Digital Transistor
(Top View)
NPN
Transistor
NPN Digital
Transistor
Digital Transistor
E C B
(Top View)
E C B
PNP
Transistor
PNP Digital
Transistor
[ Capacitors ]
Item Indication
Value
No indication...........................µF
P..............................................pF
No indication...........................50V
Dielectric
strength
All dielectric strengths other than
50V are indicated in schematic
diagrams.
[ Coils ]
Item Indication
Value
µ...............................................µH
m.............................................mH
1-9-1
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