Sharp VC-M522HM User manual

1
VC-M522HM
VC-MH722HM
VC-MH732HM
VIDEO CASSETTE RECORDER
SERVICEMANUAL
CONTENTS
Page
1. SPECIFICATIONS................................................................................................................. 3
2. DISASSEMBLY AND REASSEMBLY ................................................................................... 4
3. FUNCTION OF MAJOR MECHANICAL PARTS................................................................... 7
4. ADJUSTMENT, REPLACEMENT AND ASSEMBLY OF MECHANICAL UNITS.................. 9
5. ELECTRICAL ADJUSTMENT ............................................................................................. 28
6. MECHANISM OPERATION FLOWCHART AND TROUBLESHOOTING GUIDE .............. 31
7. ELECTRICAL TROUBLESHOOTING ................................................................................. 37
8. BLOCK DIAGRAM............................................................................................................... 54
9. SCHEMATIC DIAGRAM AND PWB FOIL PATTERN......................................................... 64
10. REPLACEMENT PARTS LIST............................................................................................ 89
11. EXPLODED VIEW OF MECHANISM PARTS..................................................................... 99
12. PACKING OF THE SET .................................................................................................... 103
SHARP CORPORATION
In the interests of user-safety (Required by safety regula-
tions in some countries) the set should be restored to its
originalconditionand onlypartsidentical tothosespecified
be used.
MODELS
VC-M522HM
VC-MH722HM
VC-MH732HM
SX9R2VC-M522H

2
VC-M522HM
VC-MH722HM
VC-MH732HM 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 D705.
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: D711 and D712.
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-M522HM
VC-MH722HM
VC-MH732HM
1. SPECIFICATIONS
Format: VHS PAL standard
Video recording system: Two rotary heads, helical scan system
Video signal: PAL colour and I signals, 625 lines
Recording/playing time: 240 min max. with SHARP E-240 tape (PAL SP)
480 min max. with an E-240 tape (LP)
Tape width: 12.7mm
Tape speed: 23.39 mm/s (PAL SP)
11.70 mm/s (PAL LP)
Antenna: 75 ohm unbalanced
Receiving channel: UHF Channel E21-E69
RF converter output signal: UHF Channel E21-E69 (Preset to CH E36)
Power requirement: AC230V ~ 240V, 50Hz
Power consumption: Approx. 17W (AC230V/50Hz) and 1W max. at Low power mode
(VC-M522HM)
Approx. 19W (AC230V/50Hz) and 1W max. at Low power mode
(VC-MH722HM/MH732HM)
Operating temperature: 5°C to 40°C
Storage temperature: –20°C to 60°C
Weight: Approx. 3.8 kg (VC-M522HM) / 4 kg (VC-MH722HM/MH732HM)
Dimensions: 430 mm (W) x 284 mm (D) x 92 mm (H)
(15-30/32" x 11-1/16" x 3-25/32")
VIDEO
Input: 1.0 Vp-p, 75 ohm
Output: 1.0 Vp-p, 75 ohm
S/N ratio: 45 dB (SP)
Horizontal resolution: 260 lines (SP mode with Super Picture)
AUDIO 0 dBs = 0.775 Vrms
Input: Line1: -3.8 dBs, 10k ohm
Line 2:-3.8 dBs, 10k ohm
Line 3:-3.8 dBs, 47k ohm
Output: Line1: -3.8 dBs, 1k ohm
Line 2:-3.8dBs, 1k ohm
REAR RCA: -3.8dBs, 1k ohm (VC-MH722HM/MH732HM)
S/N ratio: 46 dB
Frequency responce: 80 Hz ~ 10 kHz (SP mode)
80HZ ~ 5Hz (LP mode)
Hi-Fi Dynamic Range: 90 dB TYP (VC-MH722HM/MH732HM)
Hi-Fi Wow and Flutter: 0.005% (VC-MH722HM/MH732HM)
Hi-Fi Frequency Responce: 20 Hz ~ 20 k Hz (VC-MH722HM/MH732HM)
Hi-Fi Distortion: 0.5% max. (VC-MH722HM/MH732HM)
Hi-Fi Crosstalk (at 1kHz): 55 dB min. (VC-MH722HM/MH732HM)
Accessories included: 75 ohm coaxial cable
Operation manual
Infrared remote control
Battery
Note: The antenna must correspond to the new standard DIN 45325
(IEC 169 - 2) for combined UHF/VHF antenna with 75 ohm connector.
Aspartofourpolicyofcontinuousimprovement,wereservethe
right to alter design and specifications without notice.

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VC-M522HM
VC-MH722HM
VC-MH732HM
E
C1
2
1
1
8
10
5
4
C2
6
7
3
3
C1
C2
9
E
F
F
G
G
a
b
b
c
d
d
11
FRONT PANEL
MAIN FRAME
MECHANISM/
MAIN PWB
ASSEMBLY
OPERATION (2)
PWB
PWB HOLDER ANTENNA
TERMINAL
COVER
2. DISASSEMBLY AND REASSEMBLY
2-1 DISASSEMBLY OF MAJOR BLOCKS
TOP CABINET : Remove 4 screws 1.
FRONT PANEL : Remove2screws2and7clips3.
SHUTTL SWITCH: Remove 3 screws qand shuttle
switch knob.
OPERATION (1) : Remove 1 hook a. Remove 3 hooks
PWB AND PWB b.
HOLDER
F A/V PWB AND : Remove 1 screw 4and 5.
PWB HOLDER
OPERATION (2) : Remove2hookscand3hooksd.
PWB AND PWB
HOLDER
MAIN PWB/ : Remove 3 screws 6 PWB holder.
MECHANISM Remove2screws7,2screws8,2
ASSEMBLY screws 9and 1 screw 0.
TOP CABINET
F A/V PWB OPERATION (1)
PWB
SHUTTLE SWITCH
SHUTTLE SWITCH KNOB

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VC-M522HM
VC-MH722HM
VC-MH732HM
1. When removing the mechanism from the main PWB,
remove 2 screws 1and 1 screw 2and H/A shield.
Remove the antenna cover.
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.
Remove2screws4fixingthecassettehousingtothe
mechanism, and remove the cassette housing.
1
2
4
3
MAIN PWB
CASSETTE
HOUSING
MECHANISM CHASSIS
H/A SHIELD
2-2 DISASSEMBLING THE MECHANISM/MAIN PWB ASSEMBLY
ANTENNA TERMINAL COVER

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VC-M522HM
VC-MH722HM
VC-MH732HM
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.)
PARTS WHICH NEED PARTICULAR CARE
Wheninstalling themechanismchassis onthe PWBunit,
take care so as to prevent deformation due to contact of
mechanism chassis with REC TIP SW.
Pulley feed gear
Screwdriver
Casecon
drive gear
Drive angle of
cassette housing
Tilt mark (*1)
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 ofcassette housing.After ascertain-
ing the return to the initial setting position (*1) install the
2-3 CARES WHEN REASSEMBLING
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.(Fit the
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-MZ)
between the mechanism and the main PWB.
START SENSOR
AC CONNECTOR
AL CONNECTOR
REC TIP SW
AE CONNECTOR
END SENSOR

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VC-M522HM
VC-MH722HM
VC-MH732HM
3. FUNCTION OF MAJOR MECHANICAL PARTS (TOP VIEW)
1715 10
11
5
9
14
12
8
16
13
4
6
2
7
3
1
18
No. Function No. Function
1 Full erase head
2 Supply pole base ass’y
3 Tension arm ass’y
4 Idler wheel ass’y
5 Pinch drive lever ass’y
6 Supply reel disk
7 Supply main brake ass’y
8 Take-up main brake ass’y
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
15 Drum ass’y
16 Loading motor
17 Drum motor
18 Take-up pole base ass’y

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VC-M522HM
VC-MH722HM
VC-MH732HM
FUNCTION OF MAJOR MECHANICAL PARTS (BOTTOM VIEW)
26
24
21
22
19
20
12
23
No. Function No. Function
19 Slow brake
20 Master cam
21 Capstan D.D. motor
22 Reel belt
23 Clutch lever
24 Limiter pulley ass'y
12 Casecon drive gear
26 Shifter

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VC-M522HM
VC-MH722HM
VC-MH732HM
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
5. JiGRH0002 BR
JiGSG2000 BS
JiGSG0300 BF
6.
7. JiGADP003 BK
2. Torque Gauge
Tension Gauge
These Jigs are used for checking
and adjusting the reel disk height.
Whenfixinganyparttothethreaded
hole using resin with screw, use the
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.Rotarytransformerclearance
adjusting jig.
There are two gauges used for the
tension measurements, 300 g and
2.0kg.
4. Torque Driver JiGTD1200 CB
9. JiGDRiVER11055 AR
Reverse guide height
adjusting box driver This Jig is used for height adjustment of the
reverse guide (for reverse guide height ad-
justment).
Guide roller height
adjustment drive This screwdriver is used for adjusting the
guide roller height.
For X value adjustment
X value adjustment
gear type screw driver
This Jig is used for height
adjustment of the reverse guide.
13. JiGRVGH-F18 BU
12. JiGDRiVER-6 BM
Reverse Guide Height
Adjusting Jig
11. JiGDRiVERH-4 AP
Video Audio Track
625 Monoscope 6kHz 35µm
625 Monoscope 6kHz
and and 49µm
Colour bar 1kHz
VROUBZFS
10. Alignment Tape CK
VROCPSV

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VC-M522HM
VC-MH722HM
VC-MH732HM
MAINTENANCE CHECK ITEMS AND EXECUTION TIME
Perform the maintenance with the regular intervals as follows so as to maintain the quality of machine.
Parts Maintained 500
hrs. 1000
hrs. 1500 hrs. 2000 hrs. Remarks
Possible symptom
encountered
Upper and lower drum ass’y
Pinch roller
Capstan D.D. motor
Reel belt
Idler ass’y
Tension band ass’y Screen swaying
Loading motor
Limiter pulley
Supply/take-up main brake levers Tape slack
A/C head
Guide roller ass’y
Sup guide shaft
Reverse guide
Slant pole on pole base
Full erase head Colour and beating
Lateral noises Head
occasionally blocked
Smallsoundor sounddis-
tortion
Poor S/N ratio, no colour
Poorflatnessoftheenvelope
with alignment tape
Cassette not loaded or un-
loaded
No tape running, tape
slack
Cleantape contact partwith
thespecifiedcleaningliquid.
Abnormal rotation or significant vi-
bration requires replacement.
Clean rubber and rubber
contact area with the speci-
fied cleaning liquid.
Cleantapecontactareawith
thespecifiedcleaningliquid.
Notaperunning,unevencol-
our
No tape running, tape
slack, no fast forward/re-
wind motion
No tape running, tape
slack
Replace the roller of the
cleanerwhenitwearsdown.
Just change the AHC roller
assembly for new one.
AHC(Automatic head cleaner)
NOTE: : Part replacement. : Cleaning : Apply grease
<Specified> Cleaning liquid Industrial ethyl alcohol
* Thismechanismdoesnotneedelectricadjustmentwithvariableresistor.Checkparts.Ifanydeviationisfound,clean
or replace parts.