VC-MH722HM (serv.man28). Service Manual Complete - Sharp VCR Service Manual (repair manual)

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

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.

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.

Insert the sensor’s projection deep into the upper hole of the holder. Referring to the PWB, fix the sensors tight
enough.

Refer to the symbol on the PWB and the anode marking of the part.

Adjust the notch of the part to the white marker of the symbol on the PWB. Do not allow any looseness.

Be careful not to confuse the setting direction of the parts in reference to the symbols on the PWB. Do not allow any
looseness.

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.

As part of our policy of continuous improvement, we reserve the
right to alter design and specifications without notice.

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

: Remove 4 screws 

1

.

: Remove 2 screws 

2

 and 7 clips 

3

.

SHUTTL SWITCH : Remove 3 screws 

q

 and shuttle

switch knob.

OPERATION (1) : Remove 1 hook 

a

. Remove 3 hooks

b

.

HOLDER
F A/V PWB AND : Remove 1 screw 

4

 and 

5

.

PWB HOLDER
OPERATION (2) : Remove 2 hooks 

c

 and 3 hooks 

d

.

: Remove 3 screws 

6 

PWB holder.

Remove 2 screws 

7

 , 2 screws 

8

, 2

screws 

9

 and 1 screw 

0

.