Sharp vc-ga56z User manual

1
VC-GA56Z
VC-GH96Z
S60A7VC-GA56Z
SERVICE MANUAL
Intheinterestsofuser-safety(Requiredbysafetyregulations
in some countries) the set should be restored to its original
condition and only parts identical to those specified be used.
MODELS
VC-GA56Z
VC-GH96Z
VIDEO CASSETTE RECORDER
CONTENTS Page
1. GENERAL INFORMATION ...........................................................................................................3
2. DISASSEMBLY AND REASSEMBLY ........................................................................................... 5
3. FUNCTION OF MAJOR MECHANICAL PARTS........................................................................... 8
4. ADJUSTMENT, REPLACEMENT AND ASSEMBLY OF MECHANICAL UNITS ........................ 10
5. ELECTRICAL ADJUSTMENT ..................................................................................................... 29
6. MECHANISM OPERATION FLOWCHART AND TROUBLESHOOTING GUIDE ...................... 31
7. TROUBLESHOOTING ................................................................................................................ 37
8. BLOCK DIAGRAM....................................................................................................................... 48
9. SCHEMATIC DIAGRAM AND PWB FOIL PATTERN ................................................................. 57
10. PARTS LIST................................................................................................................................ 71
11. EXPLODED VIEW OF MECHANICAL PARTS ........................................................................... 79
12. PACKING OF THE SET .............................................................................................................. 83
SHARP CORPORATION

2
VC-GA56Z
VC-GH96Z
PRECAUTIONS IN PART REPLACEMENT
When servicing the unit with power on, be careful to the section marked white all over.
This is the primary power circuit which is live.
Whenchecking the soldering side in the tape travel mode, make sure first that the tape hasbeen loaded and then turn
over the PWB with due care to the primary power circuit.
Makereadjustment,ifneededafterreplacementofpart,withthemechanismanditsPWBinpositioninthemainframe.
(1) Start and end sensors: Q701 and Q702
Insert the sensor’s projection deep into the upper hole of the holder. Referring to the PWB, fix the sensors tight
enough.
(2) Photocoupler: IC901
Refer to the symbol on the PWB and the anode marking of the part.
(3) Cam switches A and B: D708 and D709.
Adjust the notch of the part to the white marker of the symbol on the PWB. Do not allow any looseness.
(4) Take-up and supply sensors: D707 and D706.
Be careful not to confuse the setting direction of the parts in reference to the symbols on the PWB. Do not allow
any looseness.

3
VC-GA56Z
VC-GH96Z
Only for VC-GH96Z
•Hi-Fi Stereo Sound
• Built-in MTS (Multi-channel TV Sound) Decoder
Common Features
• 400 Times Rewind Speed to Fast Forward and Rewind.
• EZ Set Up
• S-VHS Quasi Playback
• Double-Azimuth 4-Heads
• 19µ Clear Picture System (in EP mode)
• HQ System for Better Resolution and Color Reproduction
• Multi-Language(English/Spanish/French)OSD(OnScreen
Display) with Menu Screen Guidance
• 181-channelPLLQuartzSynthesizedRandomAccessTuner
with Automatic Channel Setting
• Quick Start with Full Loading Mechanism
• 1-Year, 8 Event Programmable Timer
• Simple Recording Timer
• Universal Remote Control
• Sharp Super Picture
• Field-Still/Variable Slow/Frame Advance
• Real-Time Counter
• Blue Screen Noise Elimination
• Auto Tracking Control System
• Digital Program Search System (DPSS)
• Skip Search
• Instant Replay
• Auto Zero Back
• Recorded Section Auto Repeat
• Full Automatic Playback
• Tamper Proof
• Up to 8 Hours of Recording and Playback (with T-160
cassette)
• Automatic Head Cleaning System
• Built in Front AV Jacks
Format: VHS NTSC Standard
Video Recording System: Rotary, Slant Azimuth Two-Head Helical Scan
Number of Video Heads: 4
Video Signal Standard: NTSC Color System
Audio Recording System: 1 Stationary Head for Linear Audio
2 Rotary Heads for Hi-Fi stereo (Only Hi-Fi models)
Tape Width: 12.7 mm (1/2 inch)
Tape Speed: (SP) 33.35 mm/sec. (1.31 i.p.s.)
(LP) 16.67 mm/sec. (0.66 i.p.s.) (playback only)
(EP) 11.12 mm/sec. (0.44 i.p.s.)
Maximum Recording Time: (SP) 160 min. (T-160)
(EP) 480 min. (T-160)
Channel Coverage: VHF 2-13
UHF 14-69
CATV 1-125
Antenna Input: 75 Ohm
Video Input: 0.5 to 2.0 Vp-p, 75 Ohm unbalanced
Video Output: 1.0 Vp-p, 75 Ohm unbalanced
Audio Input: –8 dBs, 47k Ohm unbalanced (0 dBs = 0.775 Vrms)
Audio Output: –8 dBs, 1k Ohm unbalanced (0 dBs = 0.775 Vrms)
Hi-Fi Audio (Only for Hi-Fi models): Dynamic Range: 90 dB
Frequency Response: 20 Hz-20k Hz
Memory Backup: 24 hours
Operating Temperature: 5°C to 40°C (41°F to 104°F)
Storage Temperature: –20°C to 60°C (–4°F to 140°F)
Power Source: 110 –240 V AC, 50/60 Hz
Power Consumption: 18 W
Weight: 2.8 kg
Dimensions (approx.): 360 (W) x 92.5 (H) x 255 (D) mm
Accessories included: 75 ohm coaxial cable, Operation manual, Remote control unit, Battery (2 pcs.)
AC plug adaptor (Flat ↔Round)
Note: Specifications are subject to change without notice.
1. GENERAL INFORMATION
1-1 FEATURES
1-2 SPECIFICATIONS

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VC-GA56Z
VC-GH96Z
(VC-GA56Z) (VC-GH96Z)
1-3 LOCATION OF MAJOR COMPONENTS AND CONTROL

5
VC-GA56Z
VC-GH96Z
B
C
A
B
5
9
6
10
11
7
8
3
3
C
1
12
2
4
VC-GH96Z VC-GA56Z
VC-GH96Z
11 A
ANTENNA
TERMINAL
COVER
ANTENNA
TERMINAL
COVER
TOP CABINET
SHIELD
ANGLE
MECHANISM/
MAIN PWB ASSEMBLY
FRONT PANEL
OPERATION PWB
MAIN FRAME
TOP CABINET
FIX ANGLE
2. DISASSEMBLY AND REASSEMBLY
2-1 DISASSEMBLY OF MAJOR BLOCKS
TOP CABINET : Remove 2 screws 1.
FRONT PANEL : Remove button 2.
Remove 2 screws 3and 7 clips 4.
OPERATION : Remove 1 screw 5.
PWB
SHIELD ANGLE : Remove 1 screw 6with shield angle.
MECHANISM/ : Remove 1 screw 7, 1 screw 8, 2
MAIN PWB screws 9, 2 screws 0. Remove 1
screwqwithantennaterminalcover.
Remove 1 screw wwith top cabinet
fix angle.

6
VC-GA56Z
VC-GH96Z
2-2 DISASSEMBLING THE MECHANISM/MAIN PWB ASSEMBLY
1. When removing the mechanism from the main PWB,
removetheantennacover 1screw1, andremovethe
antenna cover.
Remove the PWB bottom plate 1 screw 2.
Remove the FFC cable (AA, AD, AH) 3which con-
necting the PWB and the mechanism.
Take out vertically the mechanism so that it does not
damage the adjacent parts.
2. Removing the mechanism and cassette housing.
Remove2screws 4fixingthe cassettehousingtothe
mechanism, and remove the cassette housing.
VC-GH96Z
CASSETTE
HOUSING
MECHANISM CHASSIS
4
1
3
2
MAIN PWB

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VC-GA56Z
VC-GH96Z
2-3 CARES WHEN REASSEMBLING
INSTALLING THE CASSETTE HOUSING
Whenthecassettehousingisinstalledonthemechanism,
the initial setting is essential condition.
There are two initial setting methods, namely electrical
and mechanical.
1. Electrical initial setting
So as to perform initial setting of mechanism execute the
Step1 ofInstallation of cassettehousing. After ascertain-
ing the return to the initial setting position (*1) install the
cassette housing. (Conditions: When mechanism and
PWB have been installed)
2. Mechanical initial setting
Feed the pulley feed gear of loading motor with screw
driver. After ascertaining the return to the initial set posi-
tion (*1) install the cassette housing in the specified
position.(Thismethodisappliedonlyforthemechanism.)
INSTALLING THE MECHANISM ON PWB
Lower vertically the mechanism, paying attention to the
mechanism edge, and install the mechanism with due
care so that the parts are not damaged. So as to fix the
mechanismtothemainPWBinstalltwohousings.(Fitthe
antenna cover to one of them. For other, fix the vicinity of
loading motor and solder joint side of main PWB.) Con-
nect again the FFC cable (AA-MH, AD-ME, AH-MH)
between the mechanism and the main PWB.
PARTS WHICH NEED PARTICULAR CARE
Wheninstalling the mechanism chassis on the PWB unit,
take care so as to prevent deformation due to contact of
mechanism chassis with REC TIP SW.
Pulley feed gear
Screwdriver
Tilt mark (*1)
Casecon
drive gear
Drive angle of
cassette housing
VC-GH96Z
REC TIP SW
END SENSOR
AE CONNECTOR
AC CONNECTOR
AL CONNECTOR START SENSOR

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VC-GA56Z
VC-GH96Z
3. FUNCTION OF MAJOR MECHANICAL PARTS (TOP VIEW)
No. Function No. Function
1 Full erase head
2 Supply pole base ass’y
3 Tension arm
4 Idler wheel ass’y
5 Pinch drive lever ass’y
6 Supply reel disk
7 Supply main brake
8 Take-up main brake
9 Pinch drive cam
10 A/C head ass’y
11 Reverse guide lever ass'y
12 Casecon drive gear
13 Take-up reel disk
14 Pinch roller lever ass’y
17
15 10
11
5
9
14
12
8
16
13
4
6
2
7
3
1
18

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VC-GA56Z
VC-GH96Z
26
24
21
22
19
20
12
23
FUNCTION OF MAJOR MECHANICAL PARTS (BOTTOM VIEW)
No. Function No. Function
15 Drum ass’y
16 Loading motor
17 Drum drive motor
18 Take-up pole base ass’y
19 Slow brake lever
20 Master cam
21 Capstan D.D. motor
22 Reel belt
23 Clutch lever
24 Limiter pulley ass'y
26 Shifter

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VC-GA56Z
VC-GH96Z
4. ADJUSTMENT, REPLACEMENT AND ASSEMBLY OF MECHANICAL UNITS
Theexplanationgivenbelowrelatestotheon-sitegeneralservice(fieldservice)butitdoesnotrelatestotheadjustment
and replacement which need high-grade equipment, jigs and skill. For example, the drum assembling, replacement
and adjustment service must be performed by the person who have finished the technical courses.
4-1 MECHANISM CONFIRMATION ADJUSTMENT JIG
So as to perform completely the mechanism adjustment prepare the following special jigs. So as to maintain the initial
performance of the machine the maintenance and check are necessary. Utmost care must be taken so that the tape
is not damaged. If adjustment needs any jig, be sure to use the required jig.
JiGTG1200 CN
JiGMP0001 BY
1. Torque Cassette Meter JiGVHT-063 CZ
No. Jig ltem Part No. Code Configuration Remarks
JiGTG0090 CM
3. Torque Gauge Head JiGTH0006 AW
JiGRH0002 BR
JiGSG2000 BS
JiGSG0300 BF
7. JiGADP003 BK
Tension Gauge
These Jigs are used for checking
and adjusting the reel disk height.
Whenfixinganyparttothethreaded
holeusingresinwithscrew,usethe
jig. (Specified torque 5 kg)
Thiscassettetorquemeterisusedforcheck-
ing and adjusting the torque of take-up for
measuring tape back tension.
These Jigs are used for checking
and adjusting the torque of take-up
and supply reel disks.
Master Plane Jig and
Reel Disk Height
Adjusting Jig
Pinch pressing force
measuring jig
This Jig is used with the tension
gauge. Rotary transformer clear-
ance adjusting jig.
There are two gauges used for the
tension measurements, 300 g and
2.0 kg.
4. Torque Driver JiGTD1200 CB
8. JiGDRiVER11055 AR
Reverse guide height
adjustment box driver This Jig is used for height adjustment of the
reverse guide (for reverse guide height ad-
justment).
Thesetapesareespeciallyusedfor
electrical fine adjustment.
Video Audio HiFi Audio Track
525 Monoscope 7k — 58µm
NTSC Color Bar 1k — 58µm
VROEFZCS BG
OR
VROEFZHS BH
1k
This screwdriver is used for adjusting the
guide roller height.
For X value adjustment
This Jig is used for height
adjustment of the reverse guide.
11. JiGDRiVER-6 BM
X value adjustment
gear driver
Reverse Guide Height
Adjusting Jig
10. JiGDRiVERH-4 AP
12. JiGRVGH-F18 BU
2.3k
Black Level
(only SYNC) signal
— 19µm
2. Torque Gauge
6.
5.
9. Alignment Tape VROATSV CD
Guide roller height
adjustment driver

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VC-GA56Z
VC-GH96Z
4-2 MAINTENANCE CHECK ITEMS AND EXECUTION TIME
Perform the maintenance with the regular intervals as follows so as to maintain the quality of machine.
NOTE : Part replacement. : Cleaning : Apply grease
<Specified> Cleaning liquid Industrial ethyl alcohol
* This mechanism does not need electric adjustment with variable resistor. Check parts. If any deviation is found,
clean or replace parts.
Maintained
Parts Remarks
500
hrs. 1000 hrs. 1500 hrs. 2000 hrs. Possible symptom
encountered
Guide roller ass’y
Sup guide shaft
Reverse guide
Slant pole on pole base
Full erase head
A/C head
Upper and lower drum ass’y
Capstan D.D. motor
Pinch roller
Reel belt
Tension band ass’y
Loading motor
Idler ass’y
Limiter pulley
Supply/take-up main brake levers
AHC (Automatic Head Cleaner)
Colour and beating
Small sound or sound
distortion
Poor S/N ratio, no colour
Poor flatness of the
envelope with alignment
tape
No tape running,
uneven colour
No tape running, tape
slack
No tape running, tape
slack, no fast forward/
rewind motion
Lateral noises Head
occasionally blocked
Abnormal rotation or significant
vibration requires replacement.
Clean tape contact part with the
specified cleaning liquid.
Clean tape contact area with the
specified cleaning liquid.
Clean rubber and rubber contact
area with the specified cleaning
liquid.
Replace the roller of the cleaner
when it wears down.
Just change the AHC roller
assembly for new one.
Screen swaying
Cassette not loaded or
unloaded
No tape running, tape
slack
Tape slack
Video head cleaning procedure
1. Apply one drop of cleaning liquid to the cleaning paper with the baby oiler.
2. Gently press the cleaning paper against the video head to fix your finger, and move the upper drum so that each
head is passed to and fro 5 times (do not move the cleaning paper).
3. Wipe with the dry cleaning paper.
Notes :
•Usethecommercially availableethanol ofClass 1as
cleaning liquid.
•Sincethe video head may be damaged, do not move
up and down the cleaning paper.
•Whenever the video head is cleaned, replace the
cleaning paper.
•Do not apply this procedure for the parts other than
the video head. Parts Code Description Code
ZPAPRA56-001E Cleaning Paper AW
ZOiLR-02-24TE Babe Oiler (Spoit) AH
Gently press the cleaning paper to
fix with your finger, and rotate the
upper drum to clean.
Move to and fro 5 times for each head.
(Do not move the cleaning paper.)
Rotate the upper drum
with one hand.

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VC-GA56Z
VC-GH96Z
4-3. REMOVINGANDINSTALLINGTHECAS-
SETTE HOUSING
• Removal
1. In the cassette removing mode, remove the cassette.
2. Unplug the power cord.
3. Remove in the following numerical order.
a) Remove two screws 1.
b) Slide and pull up the cassette housing control.
1
Figure 4-1.
• Reassembly
1. Before installing the cassette housing control, short-
circuit TP803 and TP802 provided at operation PWB,
press the eject button. The casecon drive gear turns
andstopswhenthepositioningmarkappears.Engage
two teeth of casecon drive gear with the three teeth of
casecon drive angle gear, and set on the mechanism
chassis as shown below.
Casecon drive
angle gear
Casecon
drive gear
Figure 4-2.
2. Install in the reverse order of removal.
Notes:
1. When fitting the S/E sensor holder to the cassette
controller frame L/R, take care.
2. Misengagement of teeth of casecon drive gear and
drive angle gear causes malfunction. (The cassette
cannot be set, load and ejection are repeated).
3. In the case when you use the magnet screw driver,
neverapproach the magnet driver to the A/C head, FE
head, and drum.
4. When installing or removing, take care so that the
cassette housing control and tool do not contact the
guide pin or drum.
5. After installing the cassette housing control once per-
form cassette loading operation.
4-4. TORUNATAPEWITHOUTTHECASSETTE
HOUSING CONTROL ASSEMBLY
1. Remove the full-surface panel.
2. Short-circuit TP803 and TP802.
3. Plug in the power cord.
4. Turn off the power switch.
(The pole bases move into U.L.position.)
5. Open the lid of a cassette tape by hand.
6. Hold the lid with two pieces of vinyl tape.
7. Set the cassette tape in the mechanism chassis.
8. Stabilize the cassette tape with a weight (500g) to
prevent floating.
9. Turn on the power switch.
10. Perform running test.
500g
Mechanism chassis
Weight to prevent
float (500g)
Figure 4-3.
Note:
The weight should not be more than 500g.
To take out the cassette tape.
1. Turn off the power switch.
2. Take out the cassette tape.

13
VC-GA56Z
VC-GH96Z
Take-up main brake ass'y
Supply main brake ass'y
Tension band ass'y
Tension arm ass'y
Supply reel disk Take-up reel disk
4-5. REEL DISK REPLACEMENT AND
HEIGHT CHECK
• Removal
1. Remove the cassette housing control assembly.
2. Pull the tension band out of the tension arm ass'y.
3. Remove the Supply/Take-up main brake ass'y.
4. Open the hook at the top of the reel disk, and remove
the reel disk.
Note:
Take care so that the tension band ass'y and main brake
ass'y (especially soft brake) are not deformed.
Note:
•Check that the reel disk is lower than part A but higher
thanpartB.Iftheheightisnotcorrect,readjustthereel
disk height by changing the poly-slider washer under
the reel disk.
Note:
Whenthetension bandass'yis pressedinthe directionof
the arrow for removal, the catch is hard to be deformed.
• Reassembly (Supply reel disk)
1. Cleanthe reeldiskshaft andapplygrease (SC-141)to
it.
2. Match the phases of reel disk and reel relay gear, and
set the new reel disk.
3. After checking the reel disk height, wind the tension
bandass'yaroundthereeldisk,andinsertintothehole
of tension arm ass'y.
4. Assemble the Supply main brake ass'y.
Notes:
1. When installing the reel disk, take due care so that the
tensionbandass'yisnotdeformedandgreasedoesno
adhere.
2. Do not damage the Supply main brake ass'y. Be
careful so that grease does not adhere to the brake
surface.
• Reassembly (Take-up reel disk)
1. Cleanthe reeldiskshaft andapplygrease (SC-141)to
it.
2. Align the phase of the reel disk to that of the reel relay
gear and to install a new take-up reel disk onto the
shaft.
3. Checkthereeldiskheightandreassemblethetake-up
main brake ass'y.
Note:
1. Take care so that the Take-up main brake ass'y is not
damaged. Take care so that grease does not adhere
the brake surface.
2. Afterreassembly, check the video search rewind back
tension (see 4-10),andcheck thebraketorque (see4-
14).
• Height checking and adjustment
Note:
1. Set the master plane with due care so that it does not
contact the drum.
2. Whenputting the master plane,shiftthe reverse guide
a little in the loading direction. Care must be taken
since excessive shift results in damage.
Figure 4-4.
Figure 4-5.
Master plane Reverse
guide
Position
pin
Take-up reel disk
Cassette lock
release shaft
Supply reel disk
Figure 4-6.

14
VC-GA56Z
VC-GH96Z
AB
Master plane Reel disk height
adjusting jig
Mechanism chassis
10 ±0.2mm
Reel disk
Reel disk
Figure 4-7.
Torque gauge
CW
30mN·m (306gf·cm)
or more
Idler ass'y
The gauge is held at
its maximum value.
(Red mark)
Figure 4-8.
Torque gauge
30mN·m (306gf·cm)
or more
CCW
The gauge is held at
its maximum value.
(Red mark)
Supply reel disk
Idler ass'y
Figure 4-9.
Note:
Whenever replacing the reel disk, perform the height
checking and adjustment.
4-6. CHECKINGANDADJUSTMENTOFTAKE-
UP TORQUE IN FAST FORWARD MODE
• Remove the cassette housing control assembly.
• Aftershort-circuitingTP803andTP802providedat
operation PWB, plug in the power cord.
• Setting
1. Setatorquegauge tozero onthe scale.Place iton the
take-up reel disk.
2. Press the FF button.
3. To calculate the remaining capacity of the play back
mode, slowly rotate the supply reel disk, and then shift
it into the forward mode.
• Checking
1. Turn the torque gauge slowly (one rotation every 2 to
3 seconds) by hand in the CW direction.
2. Make sure that the indication of torque gauge is not
less than 30mN·m (306gf·cm).
• Adjustment
1. If the FF winding-up torque is less than the specified
value, clean the capstan D.D. motor pulley, drive belt,
andlimiterpulleywithcleaningliquid,andcheckagain.
2. If the torque is less than the set value, replace the reel
belt.
Notes:
1. Hold the torque gauge by hand so that it is not moved.
2. Do not keep the reel disk in lock state. Do not allow
long-time measurement.
4-7. CHECKING AND ADJUSTMENT OF
TAKE-UP TORQUE IN REWIND MODE
• Remove the cassette housing control assembly.
• Aftershort-circuitingTP803andTP802providedat
operation PWB, plug in the power cord.
• Setting
1. Setatorquegauge tozero onthe scale.Place iton the
supply reel disk.
2. Press the rewind button.
3. To calculate the remaining capacity, slowly rotate the
take-upreeldisk,andthenshiftitintotherewindmode.
• Checking
1. Turn the torque gauge slowly (one rotation every 2 to
3 seconds) by hand in the CCW direction.
2. Make sure that the indication of torque gauge is not
less than 30mN·m (306gf·cm).
• Adjustment
1. If the rewind winding-up torque is less than the speci-
fied value, clean the capstan D.D. motor pulley, drive
belt, and limiter pulley with cleaning liquid, rewind
again, and check the winding-up torque.
2. Ifthewinding-uptorqueisstilloutofrange, replacethe
drive belt.

15
VC-GA56Z
VC-GH96Z
Figure 4-10.
• Checking
1. Makesurethatvalueiswithinthesetting6.9±2.5mN·m
(70 ± 25gf·cm).
2. The winding-up torque fluctuates due to variation of
rotation torque of limiter pulley ass'y. Read the center
value of fluctuation as setting.
3. Set the EP record mode (x3) and make sure that the
winding-up torque is within setting.
• Adjustment
Ifthe playback winding-uptorqueis not withinthesetting,
replace the limiter pulley assembly.
Note:
When the torque cassette is set, put a weight (500g) to
prevent rise.
When the cassette torque meter is taken out.
Turn off the power switch.
Notes:
1. Hold the torque gauge by hand so that it is not moved.
2. Do not keep the reel disk in lock state. Do not allow
long-time measurement.
4-8. CHECKING AND ADJUSTMENT OF TAKE-
UPTORQUEINRECORD/PLAYBACKMODE
• Remove the cassette housing control assembly.
• After short-circuiting TP803 and TP802 provided
at operation PWB, plug in the power cord.
• Turn off the power switch.
• Open the cassette torque meter lid, and fix it with
tape.
• Load the cassette torque meter into the unit.
• Puttheweight(500g)onthecassettetorquemeter.
• Turn on the power switch.
• Pressthepicturerecord button, and set EPpicture
record mode (x3).
500g
Set value EP6.9 ±2.5mN·m (70 ±25gf·cm)
Cassette torque meter
Note:
Surely put the torque gauge on the reel disk to measure.
If the torque gauge is raised, accurate measurement is
impossible.
• Adjustment
If the rewinding playback winding-up torque is not within
the setting, replace the limiter pulley assembly.
Note:
The winding-up torque fluctuates due to variation of
rotation torque of supply reel disk. Read the center value
of fluctuation as setting.
4-9. CHECKING AND ADJUSTMENT OF
TAKE-UP TORQUE IN VIDEO SEARCH
REWIND MODE
• Remove the cassette housing control assembly.
• After short-circuiting TP803 and TP802 provided
at operation PWB, plug in the power cord.
• Setting
Press the playback button and rewind button to set the
video search rewinding mode.
• Checking
Place the torque gauge on the supply reel disk, and turn
it counterclockwise very slowly (one rotation every 1 to 2
seconds)and check that the torque is within thesetvalue
14.0 ± 3.9mN⋅m. (144 ± 40gf⋅cm)
Figure 4-11.
Torque gauge
CCW
Supply reel disk

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VC-GA56Z
VC-GH96Z
4-10. CHECKING THE VIDEO SEARCH
REWIND BACK TENSION
• Remove the cassette housing control assembly.
• Aftershort-circuitingTP803andTP802providedat
operation PWB, plug in the power cord.
• Checking
1. Afterpressingtheplaybutton,presstherewindbutton,
and set the video search rewind mode.
2. Place the torque gauge on the take-up reel disk, and
turnitcounterclockwiseveryslowly(onerotationevery
2 to 3 seconds) and check that the torque is within the
set value 3.4 ± 1.5mN⋅m (35 ± 15gf⋅cm).
Torque gauge
CCW
Take-up reel disk
Figure 4-12.
Notes:
Setthetorquegaugesecurelyonthetake-upreeldisk.
If it is not secure, the measurement will be incorrect.
4-11. CHECKING THE PINCH ROLLER
PRESSURE
• Remove the cassette housing control assembly.
• Aftershort-circuitingTP803andTP802providedat
operation PWB, plug in the power cord.
• Checking
Press the play button to set the playback mode.
1. Detach the pinch roller from the capstan shaft.
Do not separate excessively. Or the pinch lever and
pinch double action lever may disengage.
2. Engagethetensiongaugeadapterwiththepinchroller
shaft, and pull in the arrow direction.
3. Gradually return the pinch roller, and measure the
pullingforcewhenthepinchrollercontactsthecapstan
shaft.
4. Makesurethatthemeasuredvalueiswithinsetting9.0
N to 11.8 N (900 to 1,200gf).
4-12. CHECKING AND ADJUSTMENT OF
TENSION POLE POSITION
• Remove the cassette housing control assembly.
• Aftershort-circuitingTP803andTP802providedat
operation PWB, plug in the power cord.
• Setting
1. Turn off the power switch.
2. Open the cassette tape (T-120), and fix with tape.
3. Set the cassette tape in loading state.
4. Put the weight (500g) on the cassette tape.
5. Turn on the power switch.
6. Make the adjustment with the beginning of a T-120
tape.
Pinch roller
Capstan shaft
Tension gauge
900 - 1,200gf
Tension gauge adapter
Figure 4-13.
500g
(T-120)
Weight to prevent
float (500g)
Figure 4-14.
• Checking
1. Set a cassette tape, push the REC button to place the
unitintheSPrecordmode.Nowcheckthetensionpole
position.

17
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VC-GH96Z
Figure 4-15.
2. Visually check to see if the right edge of the tension
pole is within the 2.3 ± 0.25 from the right edge of the
Sup guide shaft.
2.3 ±0.25
Sup guide shaft
Tension pole
Make the adjustment with the beginning of a T-120 tape.
At left side from the center line
2.3 ±0.25
Figure 4-16.
Insertthe slottedscrewdriverin thetension pole adjuster,
and rotate counterclockwise.
At right side from the center line
2.3 ±0.25
Figure 4-17.
Insertthe slottedscrewdriverin thetension pole adjuster,
and rotate clockwise.
Tension pole adjuster adjusting range
90°
90°
Tension pole adjuster
Figure 4-18.
Adjustsothatthe deltamarkoftensionpoleadjusteris
within 90°range (left, right).
4-13. CHECKING AND ADJUSTMENT OF
RECORD/PLAYBACK BACK TENSION
• Remove the cassette housing control assembly.
• Aftershort-circuitingTP803andTP802providedat
operation PWB, plug in the power cord.
• Setting
1. Turn off the power switch.
2. Open the torque cassette meter and fix with tape.
3. Set the cassette tape in loading state.
4. Put the weight (500g) on the cassette torque meter.
5. Turn on the power switch.
500g
Weight to prevent
float (500g)
Cassette torque
meter
Figure 4-19.
• Checking
1. Pushthe REC button to place the unit in the SP record
mode.
2. Atthistimeascertain thatthebacktension iswithinthe
setting (36.5 to 52g·cm) by seeing the indication of
torque cassette meter.

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• Adjustment
1. If the indication of torque cassette meter is lower than
the setting, shift the tension spring engagement to the
part A.
2. Ifthe indication of torque cassettemeteris higher than
the setting, shift the tension spring engagement to the
part B.
4-14. CHECKING THE BRAKE TORQUE
• Checking the brake torque at the supply side
CCW: 2.9~9.8mN⋅m (30~100gf⋅cm)
CW: 4.9~13.7mN⋅m (50~140gf⋅cm)
Figure 4-21.
• Remove the cassette housing control assembly.
• Aftershort-circuitingTP803andTP802providedat
operation PWB, plug in the power cord.
• Setting
1. Setatorquegauge tozero onthe scale.Place iton the
supply reel disk.
2. Switch from the FF mode to the STOP mode.
3. Disconnect the power cord.
• Checking
Turnthetorque gaugeat arateofaboutone turn/2sec
in the CW direction/CCW direction with respect to the
supply reel disk so that the reel disk and torque gauge
pointer rotate at equal speed, and make sure that the
valueiswithinthesetting(CWdirection:4.9to13.7mN·m
(50to140gf·cm);CCWdirection:2.9to9.8mN·m(30to
100gf·cm).
Figure 4-20.
Tension arm
Tension spring
BA
Torque gauge
CCW CW
Supply reel disk
• Checking the brake torque at the take-up side
CCW: 4.9~13.7mN⋅m (50~140gf⋅cm)
CW: 3.9~10.8mN⋅m (40~110gf⋅cm)
• Remove the cassette housing control assembly.
• Aftershort-circuitingTP803andTP802providedat
operation PWB, plug in the power cord.
• Setting
1. Switch from the FF mode to the STOP mode.
2. Disconnect the power cord.
3. Setatorquegauge tozero onthe scale.Place iton the
take-up reel disk.
• Checking
1. Turnthetorque gaugeat arateofaboutone turn/2sec
inthe CCWdirection/CWdirection sothatthe reeldisk
and torque gauge pointer rotates at equal speed and
make sure that the value is within the setting (CCW
direction: 4.9 to 13.7mN·m (50 to 140gf·cm), CW
direction: 3.9 to 10.8 mN·m (40 to 110gf·cm).
2. Adjustment of the brake torque at the supply side and
the take-up side
•Unless the supply side brake torque or take-up side
braketorque iswithin thesetting, cleanthefelt surface
of reel disk (supply, take-up) brake lever, check again
the brake torque.
•Ifvaluecannotbesetwithinthesettingyet,replacethe
main brake ass'y or main brake spring.
Torque gauge
Take-up reel
disk
CW CCW
Figure 4-22.

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4-15. REPLACEMENT OF A/C (Audio/Control)
HEAD
1. Remove the cassette housing control assembly.
2. In unloading state unplug the power cord.
• Removal
1. Removethescrews123,Azimuthscrew,Tiltscrew.
2. Unsolder the PWB fitted to the A/C head.
Notes:
1. Whenreplacing, never touch the head.If you touched,
clean with the cleaning liquid.
2. When removing the screw 3, take care so that the
spring may out.
• Replacement
1. Solder the removed PWB to the new head assembly.
2. Adjust the height from the A/C head arm (lower sur-
face) to the A/C head plate to 10.8mm with slide
calipers. (3 places of azimuth screw section, tilt screw
section and A/C head front section) (Seethefigurebe-
low.)
3. Align the left end of gear of A/C head arm with the
punchedmarkofchassis,tentativelytightenthescrews
1and2so as to ensure smoothmotion of A/C head
arm. Tentative tightening torque must be 0.15 to 0.20
N·m (1.5 to 2.0kgf·cm).
Note:
1. If the screws 1and 2are tighten tentatively too
loose,theazimuthandheightofA/Cheadmaychange
whentheyarefinallytightened.Thereforecaremustbe
taken.
2. After completion of A/C head be sure to adjust tape
running.(Executetherunningadjustmentbythemethod
described in 4-18.)
Figure 4-23.
Tilt screw
3
1
2
Spring
Height screw
Azimuth screw
Figure 4-24.
Solder
New A/C head ass'y
Never touch the head
A/C head plate
A/C head PWB
10.8mm10.8mm
Figure 4-25.
1
3
2
Height screw
Left end of A/C head arm gear
Punched line mark on chassis

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4-16. A/CHEADHEIGHTROUGHADJUSTMENT
• Setting
1. Set the cassette tape in the unit.
2. Press the PLAY button to put the unit in the playback
mode.
3. Roughly adjust the height of the A/C head by turning
the height screw until the tape is in the position shown
below.
500g
Azimuth screw
Height screw Tilt screw
Cassette tape
Mechanism chassis
Weight to prevent
float (500g)
Figure 4-26.
0.3mm
A/C head
Tape
• Adjustment
Adjusttheheightscrewvisuallysothatthecontrolheadis
visible 0.3mm below the bottom of the tape.
Figure 4-27.
4-17. HEIGHT ADJUSTMENT OF REVERSE
GUIDE
1. Adjust the height from the mechanism chassis to the
reverse guide lower flange to 13.38 mm, using the
reverse guide height adjustment jig, in tape loading
state. (Refer to Figure 4-28 (a) (b).)
Reverse guide height
adjusting jig
Reverse guide
Mechanism
chassis
Reverse guide height
adjusting jig
13.38mm
Figure 4-28.
(a) (b)
2. Rotate counterclockwise the reverse guide height ad-
justment nut 1/10 turn. (For height adjustment use the
reverseguideheightadjustmentboxdriver(JiGDRiVER
11055)).
Box driver
CCW
Height adjusting nut
Figure 4-29.
3. Set the tape, and check for tape crease near the
reverse guide in the playback mode.
If crease is found, turn the reverse guide adjustment
nut to remove crease. (As for crease check refer to
Figure 4-30.)
500g
Weight to
prevent float (500g)
ACapstan
motor shaft
Fixing guide
An example of
crease near the
reverse guide
Reverse guide
Mechanism
chassis
* Check for crease from the A direction.
Figure 4-30.