Sharp VC-MH722HM (serv.man9) Service Manual ▷ View online
41
VC-M522HM
VC-MH722HM
VC-MH732HM
VC-MH722HM
VC-MH732HM
FLOW CHART NO.16 DRUM SERVO TROUBLESHOOTING
Drum servo does not function.
Check peripheral circuit of X701.
Is there 14.318MHz oscillation at
pins(37) and (38) of IC701?
NO
In PB mode
YES
In REC mode
Is there drum FG signal at pin(65)
of IC701 present?
Is the V-SYNC signal(reference) at
pin(50) of IC701?
YES
NO
NO
Check peripheral circuit of pin(50) of
IC701, C746, C747 and R745.
Check drum FG signal line.
Is the head switching pulse at pin(23)
of IC701 present?
NO
See FLOW CHART NO.15
(HEAD SWITCHING PULSE
TROUBLESHOOTING.)
YES
YES
Is the drum APC output at pin(34) of
IC701 and drum AFC output at
pin(32) of IC701 present?
NO
Replace IC701.
YES
YES
Is the drum control voltage applied
to pin(29) of IC702?
YES
Is pin(58) of IC701 in high
impedance?
NO
YES
NO
Check line between pins(34) and
(32) of IC701 and pin(29) of IC702.
Does the IC702 operate normally?
Replace IC701.
Replace drum motor.
42
VC-M522HM
VC-MH722HM
VC-MH732HM
VC-MH722HM
VC-MH732HM
1
2
FLOW CHART NO.17 CAPSTAN SERVO TROUBLESHOOTING
Capstan servo does not function.
Only PB mode inoperative
YES
Only REC mode inoperative
YES
YES
NO
YES
NO
NO
NO
NO
NO
Check peripheral
circuit of pin(50) of
IC701, C746, C747
and R745.
Is there 14.318MHz
oscillation at pins
(37) and (38) of
IC701?
Check peripheral
circuit of X701.
YES
YES
Dose pin(59) of
IC701 operate
normally?
Check "
1
"
Check "
2
"
Check capstan
motor unit and/or
replace.
Is there capstan
AFC and APC
at pins(31) and (33)
of IC701?
Replace IC701.
Replace A/C head.
YES
YES
YES
NO
NO
NO
Is there capstan
AFC signal at pin
(31) of IC701?
NO
NO
NO
Is there capstan
APC signal at pin
(33) of IC701?
YES
NO
Replace IC701.
Does PB CTL
signal appear at
pin (76) of IC701?
Replace IC701.
Is there REC CTL
signal output at
pins(75) and (74)
of IC701?
Does PB CTL
signal appear at
pin(76) of IC701?
Does A/C head
operate normally?
Adjust the height
of the A/C head.
Does the capstan
FG signal appear
at pin (67) of IC-
701?
Check the capstan
FG signal line bet-
ween pin(6) of AC
connector and pin
(67) of IC701.
Check peripheral
circuit of AC
connector.
Is the V-SYNC
signal(reference) at
pin(50) of IC701?
Are REC and/or PB
mode inoperative?
43
VC-M522HM
VC-MH722HM
VC-MH732HM
VC-MH722HM
VC-MH732HM
Is there picture signal inputted
at pins(28) and (31) of IC201?
Is there picture signal outputted
at pin(52) of IC201?
*Check line between DECODER block and pin(31) of IC201.
See FLOW CHART NO.23 DECODER TROUBLESHOOTING.
*Check line between front video input terminal and pin(28) of IC201.
Check PC 5V line.
FLOW CHART NO.18 E-E MODE TROUBLESHOOTING
No picture E-E signal.
Is there picture signal outputted
at emitter of Q211?
Is there picture signal inputted
at pin(49) of IC701?
Is there picture signal outputted
at pin(47) of IC701?
Is there picture signal outputted
at emitter of Q709?
Is there picture signal outputted
at emitter of Q708?
(1)RF output : Is there picture
signal inputted at RF video in-
put terminal of tuner?
(2)Line output : Is there picture
signal inputted at pin(19) of
IC2501?
Is there picture signal outputted
at pins(20),(23) of IC2501?
Check the line between IC2501
peripheral and output terminal
periphery.
Is the supply voltage of 5V(Y-
Vcc) fed to pin(12) of IC201?
Is there Y/C serial data and
Y/C clock signal applied to pins
(63) and (62) of IC201?
Replace IC201.
Check line between pin(52) of
IC201 and Q211.
Check line between Sync tip
clamp circuit, and pin(49) of
IC701?
Is the supply voltage of 5V
(OSD Vcc) fed to pin(51) of
IC701?
Check peripheral circuit of
Q709.
Check line between Q709 and
Q708.
RF output : Check the line between Q708 peripheral and RF
video input terminal of tuner(TU1551) periphery.
Check line between Q708 and IC2501.
Check peripheral circuit of
IC2501.
Check line between pins
(63),(62) of IC201, and pins
(56),(57) of IC701.
Check PC 5V line.
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
44
VC-M522HM
VC-MH722HM
VC-MH732HM
VC-MH722HM
VC-MH732HM
FLOW CHART NO.19 RECORDING MODE TROUBLESHOOTING
Picture(Luminance) record is impossible.(E-E mode is possible.)
Is there luminance signal inputted at pin(19)
of IC201?
YES
NO
Is there luminance signal inputted at pin(42)
of IC201?
YES
NO
Is there luminance signal inputted at pin(26)
of IC201?
YES
NO
Is there luminance signal inputted at pin(23)
of IC201?
YES
NO
Is there luminance signal input and output at
pins(13) and (14) of IC201, respectively?
Check or replace the cylinder.
YES
NO
SP mode : Is there record FM signal(approx.20mVp-p) output at pins(88),(89)((SP1)) and pins(86),(87)
((SP2)) of IC201?
LP(PAL,SECAM) mode : Is there record FM signal(approx.20mVp-p) output at pins(93),(94)((EP1)) and
pins(92),(91) ((EP2)) of IC201? (For VC-MH742HM)
YES
Check line between pins(18) and (19) of IC201.
Check line between pins(21) and (42) of
IC201.(C208)
Check line between pins(39) and (26) of
IC201.(C212)
Is there luminance signal outputted at pin(39)
of IC201?
YES
Is voltage 5V applied to the CCD section
power terminal at pin(36) of IC201?
YES
Is CCD control voltage approx. 0V applied
normally to the pin(37) from pin(57) of IC201?
Is clock signal for CCD applied normally to
the pin(44) from (69) of IC201?
YES
Although picture record is possible, colour does not appear. (E-E mode is possible.)
Is voltage of 5V applied to the chroma section
power terminal pin(61) of IC201?
YES
NO
Is there chroma signal inputted at pin(46) of
IC201?
YES
NO
Is there chroma signal inputted at pin(58) of
IC201?
YES
NO
NO
Check peripheral circuit pin(61) of IC201 and
PC 5V line.
Check line between pin(60) and pin(46) of
IC201.(C512)
YES
Is the supply voltage of 5V(PRE/REC Vcc)
fed to pin(90) of IC201?
NO
Replace IC201.
Check whether the pins(73) and (75) of IC201
oscillate 4.43MHz.
Check parts around of X501.
Is there chroma signal outputted at pin(35) of
IC201?
YES
Check line between pins(58) and (35) of
IC201.
YES
YES
Check line betwen pins(24) and (23) of IC201.
(C210)
Check peripherlal circuit of pins(13) and (14)
of IC201.(R201,R202,C203,C225)
SP mode : Is there chroma ingredient included signal(approx.20mVp-p) output at pins(88),(89)((SP1))
and pins(86),(87)((SP2)) of IC201?
LP(PAL,SECAM)mode : Is there chroma ingredient included signal(approx.20mVp-p) output at pins
(93),(94)((EP1)) and pins(92),(91)((EP2)) of IC201? (For VC-MH742HM)
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