Sharp VC-A422U User manual

1
VC-A422U
VC-H822U
S41S7VC-A422U
SERVICE MANUAL
This document has been published to be used for
after sales service only.
The contents are subject to change without notice.
SHARP CORPORATION
VIDEO CASSETTE RECORDER
MODELS VC-A422U/H822U
VIDEO CASSETTE RECORDER
In the interests of user-safety (Required by safety regula-
tions in some countries) the set should be restored to its
original condition and only parts identical to those specified
be used.
VC-A422U
VC-H822U
CONTENTS
Page
1. GENERAL INFORMATION ...........................................................................................................5
2. DISASSEMBLY AND REASSEMBLY ........................................................................................... 7
3. FUNCTION OF MAJOR MECHANICAL PARTS......................................................................... 10
4. ADJUSTMENT, REPLACEMENT AND ASSEMBLY OF MECHANICAL UNITS........................ 12
5. ELECTRICAL ADJUSTMENT ..................................................................................................... 31
6. MECHANISM OPERATION FLOWCHART AND TROUBLESHOOTING GUIDE ...................... 33
7. TROUBLESHOOTING ................................................................................................................ 39
8. BLOCK DIAGRAM....................................................................................................................... 50
9. SCHEMATIC DIAGRAM AND PWB FOIL PATTERN ................................................................. 58
10. REPLACEMENT PARTS LIST .................................................................................................... 73
11. EXPLODED VIEW OF MECHANICAL PARTS ........................................................................... 80
12. PACKING OF THE SET .............................................................................................................. 84
VC-A422U/H822U .......... Models for U.S.A. and Canada
VC-A422U
VC-H822U
MODELS
SERVICE MANUAL

2
VC-A422U
VC-H822U
IMPORTANT SERVICE NOTES
WARNING :TOREDUCE THE RISK OF FIRE OR ELEC-
TRIC SHOCK, DO NOT EXPOSE THIS AP-
PLIANCE TO RAIN OR MOISTURE.
RISK OF ELECTRIC SHOCK
DO NOT OPEN
CAUTION
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK. DO
NOT REMOVE COVER. NO USER-SERVICEABLE
PARTS INSIDE. REFER SERVICING TO QUALIFIED
SERVICE PERSONNEL.
This symbol warns the user of uninsulated voltage
withintheunit thatcancausedangerouselectricshocks.
This symbol alerts the user that there are important
operating and maintenance instructions in the literature
accompanying this unit.
This symbol mark means fast operating fuse.
For continued protection against risk of fire, replace
only with same type fuse F901 (3.0A, 125V).
CAUTION:
BEFORE RETURNING THE VIDEO CASSETTE
RECORDER
Before returning the video cassette recorder to the user,
perform the following safety checks.
1. Inspect all lead dress to make certain that leads are
not pinched or that hardware is not lodged between
the chassis and other metal parts in the video cassette
recorder.
2. Inspect all protective devices such as non-metallic
control knobs, insulation materials, cabinet backs,
adjustment and compartment covers or shields, isola-
tion resistor/capacitor networks, mechanical insula-
tors etc.
3. To be sure that no shock hazard exists, check for
current in the following manner.
●Plug the AC line cord directly into a 120 volt AC outlet
(Do not use an isolation transformer for this test).
●Using two clip leads, connect a 1.5k ohm, 10 watt
resistor paralleled by a 0.15µF capacitor in series with
all exposed metal cabinet parts and a known earth
ground, such as a water pipe or conduit.
●Use an SSVM or VOM with 1000 ohm per volt, or
higher, sensitivity or measure the AC voltage drop
across the resistor (See Diagram).
●Move the resistor connection to earth exposed metal
part having a return path to the chassis (antenna,
metal cabinet, screw heads, knobs and control shafts,
SSVM
AC SCALE
1.5k ohms.
10W
CONNECT TO
KNOWN EARTH
GROUND
TO EXPOSED
METAL PARTS
0.15 µF
TEST PROBE
etc.) and measure the AC voltage drop across the
resistor. Reverse the AC plug on the set and repeat
AC voltage measurements for each exposed part.
Any reading of 0.45V rms (this corresponds to 0.3mA
rms AC.) or more is excessive and indicates a poten-
tial shock hazard which must be corrected before
returning the video cassette recorder to the owner.
3.0A 125V

3
VC-A422U
VC-H822U
NOTES DE SERVICE IMPORTANTES
ATTENTION: POUR REDUIRE LES RESQUES D'IN-
CENDIE OU DE CHOC ELECTRIQUE,
NE PAS EXPOSER CET APPAREIL A
LA PLUIE OU A L'HUMIDITE.
RISQUE DE CHOC ELECTRIQUE
NE PAS OUVRIR
ATTENTION
Ce symbole avertit l'utilisateur que des instructions
importantes relatives à l'utilisation et àl'entretien se
trouvent dans le manuel accompagnant l'appareil.
ATTENTION: AFIN DE REDUIRE LES RISQUES DE CHOC
ELECTRIQUE,NEPASRETIRERLECOUVERCLE,
AUCUN ORGANE INTERNE NE PEUT ETRE
REPARE PAR L'UTILISATEUR. CONFIER
L'APPAREIL A UN DEPANNEUR QUALIFIE.
Ce symbole signale à l'utilisateur la présence d'une
tension non isolée à l'intérieur de l'appareil qui peut être
la cause de secousses électriques dangereuses.
PRECAUTION:
Cette marque indique le fusible à action in stantansée.
Pour la protection continue contre le risque d'incendie,
ne remplacer que par le fusible type F901 (3,0A, 125V).
AVANT DE RENDRE LE MAGNETOSCOPE
Avantderendrele magnétoscope à l’utilisateur, effectuer
les vérifications de sécurité suivantes.
1. Vérifier toutes les gaines de fil pour être sûr que les fils
ne sont pas pincés ou que le matériel n’est pas coincé
entre le châssis et les autres pièces métalliques dans
le magnétoscope.
2. Vérifier tous les dispositifs de protection tels que les
boutons de commande non métalliques, les matériaux
d’isolement, le dos du coffret, les couvercles de
compartiment et ajustement ou les boucliers, les
réseaux de résistance / condensateur d’isolement, Ies
isolateurs mécaniques, etc.
3. Pourêtresûrqu’iln’yaaucunrisquedechocélectrique,
vérifier le courant de fuite de la maniére suivante.
●Brancherle cordon d’alimentation secteur directement
dansune prise de courant de 120 volts. (Ne pasutiliser
de transformateur d’isolement pour cet essai).
●Utiliser deux fils à pinces et connecter une résistance
de10watts1,5kohmenparallèleavecuncondensateur
de 0,15 µF en série avec des pièces du coffret
métallique exposées et une masse de terre connue
telle qu’un tuyau ou un conduit d’eau.
●Utiliserun VTVM ou VOM avec unesensibilitéde 1000
ohms par volt ou plus ou mesurer la chute de tension
CA entre la résistance (voir diagramme).
●Déposer la connexion de la résistance à toutes les
pièces métalliques exposées ayant un parcours de
retour au châssis (connexions d’antenne, coffret
métallique, tétes de vis, boutons et arbres de
commande, etc.) et mesurer la chute de tension CA
entre la résistance. Inverser la fiche CA (une fiche
intermédiaire non polarisée doit être utilisée à seule fin
de faire ces vérifications.) sur l’appareil et répéter les
mesures de tension CA pour chaque piéce métallique
exposée. Toute lecture de 0,45 Vrms (ceci correspond
à 0,3 mArms CA) ou plus est excessive et signale un
danger de choc qui doit être corrigé avant de rendre le
magnétoscope à son utilisateur.
0,15 µF
SONDE D'ESSAI
VERS PIECES
METALLIQUES
EXPOSEES
VTVM
ECHELLE CA
1,5 KOHMS
10W
CANNECTER A
UNE MASSE DE
TERRE CONNUE
3,0A 125V

4
VC-A422U
VC-H822U
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.
When checking the soldering side in the tape travel mode, make sure first that the tape has been loaded and then turn
over the PWB with due care to the primary power circuit.
Make readjustment, if needed after replacement of part, with the mechanism and its PWB in position in the main frame.
(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.

5
VC-A422U
VC-H822U
1. GENERAL INFORMATION
1-1 FEATURES
Only for VC-H822U
•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
•19
µClear Picture System (in EP mode)
• HQ System for Better Resolution and Color Reproduction
• Multi-Language (English/Spanish/French) OSD (On Screen
Display) with Menu Screen Guidance
• 181-channelPLLQuartzSynthesizedRandomAccessTuner
with Automatic Channel Setting
• Quick Start with Full Loading Mechanism
• 1-Year, 8 Event Programmable Timer
• Remote Control
• 5 sec. Timer Backup
• Field-Still/Variable Slow/Frame Advance
• Real-Time Counter (On Screen Display)
• Automatic Daylight Saving-Time (D.S.T.) Adjustment
• 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
1-2 SPECIFICATIONS
Format: VHS NTSC Standard
Video Recording System: Rotary, Slant Azimuth Two-Head Helical Scan System
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 model)
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, 47 kOhm unbalanced (0 dBs = 0.775 Vrms)
Audio Output: –8 dBs, 1 kOhm unbalanced (0 dBs = 0.775 Vrms)
Hi-Fi Audio:
Dynamic Range: 90 dB
Frequency Response: 20 Hz-20 kHz
Memory Backup: 5 sec.
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: 120 V AC, 60 Hz
Power Consumption: 18 W
Dimensions (approx.): 360 (W) x 92 (H) x 253.5 (D) mm (14-3/16" x 3-5/8" x 9-63/64")
Weight (approx.): 2.7 kg (6 lbs)
Accessories included: 75 ohm coaxial cable, Operation manual, Infrared remote control, Battery (2 pcs.)
Note:Specifications are subject to change without notice.

6
VC-A422U
VC-H822U
1-3 LOCATION OF MAJOR COMPONENTS AND CONTROL
Cassette compartment (see Playback/Recording)
POWER button (When pressed to turn on the VCR, the LCD backlight will light up. When the power is turned off, the LCD backlight will light off.)
Basic function controls (see Playback/Recording)


7
VC-A422U
VC-H822U
B
C
A
B
4
7
5
8
6
2
2
C
1
A
9
8
VC-A422U
VC-H822U
3
VC-H822U
VC-A422U
2. DISASSEMBLY AND REASSEMBLY
2-1 DISASSEMBLY OF MAJOR BLOCKS
TOP CABINET : Remove 2 screws 1.
FRONT PANEL : Remove 2 screws 2and 7 clips 3.
OPERATION : Remove 1 screw 4.
PWB
SHIELD ANGLE : Remove 1 screw 5with shield angle.
MECHANISM/ : Remove 1 screw 6, 2 screws 7.
MAIN PWB Remove 1 screw 8with antenna
terminal cover. Remove 1 screw 9
with top cabinet fix angle.
MAIN FRAME
SHIELD
ANGLE
TOP CABINET
TOP CABINET
FIX ANGLE
OPERATION PWB
LCD ASS'Y
MECHANISM/
MAIN PWB
ASSEMBLY
ANTENNA
TERMINAL
COVER
ANTENNA
TERMINAL
COVER
H/A SHIELD
(Bottom)
FRONT AV JACK
FRONT PANEL

8
VC-A422U
VC-H822U
MECHANISM CHASSIS
2-2 DISASSEMBLING THE MECHANISM/MAIN PWB ASSEMBLY
1. When removing the mechanism from the main PWB,
remove the antenna cover 1 screw 1, and remove the
antenna terminal cover.
Remove the FFC cable (AA, AD, AH) 3which connect-
ing 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.
Remove 2 screws 4fixing the cassette housing to the
mechanism, and remove the cassette housing.
1
3
4
CASSETTE
HOUSING
MAIN PWB
VC-H822U
VC-A422U

9
VC-A422U
VC-H822U
START SENSOR
2-3 CARES WHEN REASSEMBLING
INSTALLING THE CASSETTE HOUSING
When the cassette housing is installed on the mechanism,
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
Step 1 of Installation of cassette housing. After ascertaining
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 position
(*1) install the cassette housing in the specified position.
(This method is applied only for the mechanism.)
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 mecha-
nism to the main PWB install two housings. (Fit the antenna
cover to one of them. For other, fix the vicinity of loading
motor and solder joint side of main PWB.) Connect again
the FFC cable (AA-MH, AD-ME, AH-MH) between the
mechanism and the main PWB.
PARTS WHICH NEED PARTICULAR CARE
When installing 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
AE CONNECTOR
AL CONNECTOR
Casecon
drive gear
Drive angle of
cassette housing
REC TIP SW
END SENSOR
AC CONNECTOR
Tilt mark (*1)
VC-H822U
VC-A422U

10
VC-A422U
VC-H822U
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

11
VC-A422U
VC-H822U
FUNCTION OF MAJOR MECHANICAL PARTS (BOTTOMVIEW)
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
25 Shifter
25
24
21
22
19
20
12
23

12
VC-A422U
VC-H822U
4. ADJUSTMENT, REPLACEMENT AND ASSEMBLY OF MECHANICAL UNITS
The explanation given below relates to the on-site general service (field service) but it does not relates to the adjustment
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.
When fixing any part to the threaded
hole using resin with screw, use the
jig. (Specified torque 5 kg)
This cassette torque meter is used for check-
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.Rotarytransformerclearance
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).
These tapes are especially used for
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

13
VC-A422U
VC-H822U
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 :
• Use the commercially available ethanol of Class 1 as
cleaning liquid.
• Since the video head may be damaged, do not move up
and down the cleaning paper.
• Whenever the video head is cleaned, replace the clean-
ing 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.

14
VC-A422U
VC-H822U
Figure 4-1.
• Reassembly
1. Before installing the cassette housing control, short-
circuit between TP803 and TP802 provided at operation
PWB, press the eject button. The casecon drive gear
turns and stops when the positioning mark appears.
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.
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, never
approach 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 between 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.
4-3 REMOVING AND INSTALLING THE CAS-
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
Casecon
drive gear Casecon drive
angle gear
500g
Figure 4-3.
Mechanism chassis
Weighttoprevent
float (500g)
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.

15
VC-A422U
VC-H822U
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.
4. Assemble the Supply main brake ass'y.
Notes:
1. When installing the reel disk, take due care so that the
tension band ass'y is not deformed and grease does no
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. Clean the reel disk shaft and apply grease (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. Check the reel disk height and reassemble the take-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. After reassembly, check the video search rewind back
tension (see 4-10), and check the brake torque (see 4-
14).
• Height checking and adjustment
Note:
1. Set the master plane with due care so that it does not
contact the drum.
2. When putting the master plane, shift the reverse guide
a little in the loading direction. Care must be taken since
excessive shift results in damage.
Figure 4-6.
Note:
• Check that the reel disk is lower than part A but higher
than part B. If the height is not correct, readjust the reel
disk height by changing the poly-slider washer under the
reel disk.
Figure 4-4.
Note:
When the tension band ass'y is pressed in the direction of
the arrow for removal, the catch is hard to be deformed.
Figure 4-5.
• Reassembly (Supply reel disk)
1. Clean the reel disk shaft and apply grease (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
band ass'y around the reel disk, and insert into the hole
of tension arm ass'y.
Tension arm ass'y
Supply reel disk Take-up reel disk
Master plane
Reverse
guide
Position
pin
Take-up main brake ass'y
Supply reel disk
Cassette lock
release shaft
Take-up reel disk
Tension band ass'y
Supply main brake ass'y

16
VC-A422U
VC-H822U
Note:
Wheneverreplacingthe reel disk, perform the height check-
ing and adjustment.
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.
• After short-circuiting between TP803 and TP802
provided at operation PWB, plug in the power cord.
• Setting
1. Set a torque gauge to zero on the scale. Place it on the
supply reel disk.
2. Press the rewind button.
3. To calculate the remaining capacity, slowly rotate the
take-up reel disk, and then shift it into the rewind mode.
• 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).
AB
Figure 4-7.
Master plane Reel disk height
adjusting jig
Mechanism chassis
Reel disk
10 ±0.2mm Reel disk
4-6 CHECKING AND ADJUSTMENT OF TAKE-
UP TORQUE IN FAST FORWARD MODE
• Remove the cassette housing control assembly.
• After short-circuiting between TP803 and TP802
provided at operation PWB, plug in the power cord.
• Setting
1. Set a torque gauge to zero on the scale. Place it on 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).
Figure 4-9.
Torque gauge
30mN·m (306gf·cm)
or more
Supply reel disk
Idler ass'y
The gauge is held at
its maximum value.
(Red mark)
• Adjustment
1. If the rewind winding-up torque is less than the specified
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. If the winding-up torque is still out of range, replace the
drive belt.
Figure 4-8.
Torque gauge
30mN·m (306gf·cm)
or more
The gauge is held at
its maximum value.
(Red mark)
Idler ass'y
• Adjustment
1. If the FF winding-up torque is less than the specified
value, clean the capstan D.D. motor pulley, drive belt,
and limiter pulley with cleaning liquid, and check again.
2. If the torque is less than the set value, replace the reel
belt.
CCW
CW

17
VC-A422U
VC-H822U
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-
UP TORQUE IN RECORD/PLAYBACK
MODE
• Remove the cassette housing control assembly.
• After short-circuiting between 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.
• Put the weight (500g) on the cassette torque meter.
• Turn on the power switch.
• Press the picture record button, and set EP picture
record mode (x3).
4-9 CHECKING AND ADJUSTMENT OF TAKE-
UP TORQUE IN VIDEO SEARCH REWIND
MODE
• Remove the cassette housing control assembly.
• After short-circuiting between 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 the set value
14.0 ±3.9mN⋅m. (144 ±40gf⋅cm)
Set value EP6.9 ±2.5mN⋅m (70 ±25gf⋅cm)
500g
Cassette torque meter
Figure 4-10.
• Checking
1. Make sure that value is within the setting 6.9 ±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
If the playback winding-up torque is not within the setting,
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.
Figure 4-11.
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 rota-
tion torque of supply reel disk. Read the center value of
fluctuation as setting.
Torque gauge
Supply reel disk
CCW

18
VC-A422U
VC-H822U
Figure 4-13.
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. Engage the tension gauge adapter with the pinch roller
shaft, and pull in the arrow direction.
3. Gradually return the pinch roller, and measure the
pulling force when the pinch roller contacts the capstan
shaft.
4. Make sure that the measured value is within setting 8.8
N to 11.8 N (900 to 1,200gf).
4-12 CHECKING AND ADJUSTMENT OF
TENSION POLE POSITION
• Remove the cassette housing control assembly.
• After short-circuiting between TP803 and TP802
provided at 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.
4-10 CHECKINGTHEVIDEOSEARCHREWIND
BACK TENSION
• Remove the cassette housing control assembly.
• After short-circuiting between TP803 and TP802
provided at operation PWB, plug in the power cord.
• Checking
1. After pressing the play button, press the rewind button,
and set the video search rewind mode.
2. Place the torque gauge on the take-up reel disk, and turn
it counterclockwise very slowly (one rotation every 2 to
3 seconds) and check that the torque is within the set
value 3.4 ±1.5mN⋅m (35 ±15gf⋅cm).
Pinch roller Tension gauge
900 - 1,200gf
Capstan shaft
Tension gauge adapter
Figure 4-12.
Torque gauge
Take-up reel disk
Notes:
Set the torque gauge securely on the take-up reel disk.
If it is not secure, the measurement will be incorrect.
4-11 CHECKING THE PINCH ROLLER
PRESSURE
• Remove the cassette housing control assembly.
• After short-circuiting between TP803 and TP802
provided at operation PWB, plug in the power cord.
• Checking
Press the play button to set the playback mode.
CCW
Figure 4-14.
500g
(T-120)
Weight to prevent
float (500g)
• Checking
1. Set a cassette tape, push the REC button to place the
unit in the SP record mode. Now check the tension pole
position.

19
VC-A422U
VC-H822U
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.
Insert the slotted screwdriver in the tension pole adjuster,
and rotate clockwise.
Figure 4-17.
At left side from the center line
Figure 4-15.
Figure 4-16.
Insert the slotted screwdriver in the tension pole adjuster,
and rotate counterclockwise.
At right side from the center line
Tension pole adjuster adjusting range
2.3 ±0.25
2.3 ±0.25
2.3 ±0.25
Sup guide shaft
Adjust so that the delta mark of tension pole adjuster is
within 90°range (left, right).
4-13 CHECKING AND ADJUSTMENT OF
RECORD/PLAYBACK BACK TENSION
• Remove the cassette housing control assembly.
• After short-circuiting between TP803 and TP802
provided at 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.
Make the adjustment with the beginning of a T-120 tape.
Tension pole adjuster
90°
90°
Figure 4-18.
Tension pole
500g
Weight to prevent
float (500g)
Cassette torque
meter
Figure 4-19.
• Checking
1. Push the REC button to place the unit in the SP record
mode.
2. At this time ascertain that the back tension is within the
setting (36.5 to 52g·cm) by seeing the indication of
torque cassette meter.

20
VC-A422U
VC-H822U
• Adjustment
1. If the indication of torque cassette meter is lower than
the setting, shift the tension spring engagement to the
part A.
2. If the indication of torque cassette meter is higher than
the setting, shift the tension spring engagement to the
part B.
• Checking the brake torque at the take-up side
Figure 4-22.
CCW: 4.9~13.7mN⋅m (50~140gf⋅cm)
CW: 3.9~10.8mN⋅m (40~110gf⋅cm)
• Remove the cassette housing control assembly.
• After short-circuiting between TP803 and TP802
provided at operation PWB, plug in the power cord.
• Setting
1. Switch from the FF mode to the STOP mode.
2. Disconnect the power cord.
3. Set a torque gauge to zero on the scale. Place it on the
take-up reel disk.
• Checking
1. Turn the torque gauge at a rate of about one turn/2 sec
in the CCW direction/CW direction so that the reel disk
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 direc-
tion: 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
brake torque is within the setting, clean the felt surface
of reel disk (supply, take-up) brake lever, check again
the brake torque.
• If value cannot be set within the setting yet, replace the
main brake ass'y or main brake spring.
Figure 4-20.
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.
• After short-circuiting between TP803 and TP802
provided at operation PWB, plug in the power cord.
• Setting
1. Set a torque gauge to zero on the scale. Place it on the
supply reel disk.
2. Switch from the FF mode to the STOP mode.
3. Disconnect the power cord.
• Checking
Turn the torque gauge at a rate of about one turn/2 sec
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
valueis within thesetting (CW direction: 4.9to 13.7mN·m
(50 to 140gf·cm); CCW direction: 2.9 to 9.8mN·m (30 to
100gf·cm).
Tension arm
Tension spring
CW
CCW CW
Supply reel disk
Torque gauge
Torque gauge
CCW
Take-up reel
disk
AB