Sharp VC-MH85 (serv.man4) Service Manual ▷ View online
45
VC-MH705HM/LM
VC-MH815HM/LM,MH85HM
VC-MH715HM,MH835HM
FLOW CHART NO.17 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?
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?
IC701 present?
Is the C-SYNC signal(reference) at pin
(50) of IC701?
(50) of IC701?
YES
NO
NO
Check peripheral circuit of pin(50) of
IC701, C716, C715 and R708.
IC701, C716, C715 and R708.
Check drum FG signal line.
Is the head switching pulse at pin (23) of
IC701 present?
IC701 present?
NO
See FLOW CHART NO.16
(HEAD SWITCHING PULSE TROUBLE-
SHOOTING.)
(HEAD SWITCHING PULSE TROUBLE-
SHOOTING.)
YES
YES
Is the drum APC output at pin (34) of
IC701 and drum AFC output at pin(32) of
IC701 present?
IC701 and drum AFC output at pin(32) of
IC701 present?
NO
Replace IC701.
YES
YES
Is the drum control voltage applied to
pin(12) of P701?
pin(12) of P701?
YES
Is pin(30) of IC701 in high impedance?
NO
YES
Check line between pins(34) and (32) of
IC701 and pin(12) of P701.
IC701 and pin(12) of P701.
Does the IC on mechanism operate
normally?
normally?
Replace IC701.
Replace drum motor.
NO
1
FLOW CHART NO.18 CAPSTAN SERVO TROUBLESHOOTING
Capstan servo does not function.
Only PB mode inoperative
YES
NO
Check "
1
"
Check capstan motor unit and/or replace.
Is there capstan AFC and APC signal at
pins(31) and (33) of IC701?
pins(31) and (33) of IC701?
Replace A/C head.
YES
NO
YES
NO
NO
YES
NO
Replace IC701.
NO
Is there REC CTL signal output at pins
(74) and (75) of IC701?
(74) and (75) of IC701?
Does PB CTL signal appear at pin (76) of
IC701?
IC701?
Does A/C head operate normally?
Adjust the height of the A/C head.
Check the capstan FG signal line between
pin(1) of P701 and pin(67) of IC701?
pin(1) of P701 and pin(67) of IC701?
Check peripheral circuit at pin(1) of P701.
Are REC and/or PB mode inoperative?
Check "
2
"
NO
YES
YES
Does pin(29) of IC701 operate normally?
NO
NO
Is there capstan APC signal at pin (33)
of IC701?
of IC701?
Does PB CTL signal appear at pin (76) of
IC701?
IC701?
Replace IC701.
2
Only REC mode inoperative
NO
Check peripheral circuit of pin(50) of
IC701, C716, C715 and R708.
IC701, C716, C715 and R708.
Is the C-SYNC signal(reference) at pin(50)
of IC701?
of IC701?
YES
YES
Does the capstan FG signal appear at pin
(67) of IC701?
(67) of IC701?
YES
NO
NO
Check peripheral circuit of X701.
Is there 14.318MHz oscillation at pins(37)
and (38) of IC701?
and (38) of IC701?
A
A
46
VC-MH705HM/LM
VC-MH815HM/LM,MH85HM
VC-MH715HM,MH835HM
No picture E-E signal. (by pass)
Is picture signal input into the pins(31) and (32) of IC201?
YES
YES
YES
YES
NO
NO
NO
NO
NO
Check the line between pin(24) of TU101 and pin(31) of IC201.
Check the line between external video input terminal (J201) and
pin(31) of IC201.
Check the line betweem video input terminal and pin(28) of IC201.
Check the line between external video input terminal (J201) and
pin(31) of IC201.
Check the line betweem video input terminal and pin(28) of IC201.
Is picture signal outputted to the pin(52) of IC201?
Check the line between pins(63) and (62) of IC201
and all the way up thru to pins(84) and (85) of IC701.
and all the way up thru to pins(84) and (85) of IC701.
Is picture signal output to the emitter of video output buffer
(Q251)?
(Q251)?
1
Line output: Check video output buffer(Q251) peripheral and output terminal periphery.
2
RF output: Check video output buffer(Q251) peripheral and video input terminal of RF converter periphery.
Is supply voltage of 5V(Y-Vcc) fed to the pin(12) of IC201?
Check the PC 5V line.
Is there Y/C serial data and Y/C signal clock applied
to the pins(63) and (62) of IC201?
to the pins(63) and (62) of IC201?
Check peripheral circuit of Q251.
FLOW CHART NO.19 E-E MODE TROUBLESHOOTING
47
VC-MH705HM/LM
VC-MH815HM/LM,MH85HM
VC-MH715HM,MH835HM
Picture (Luminance) record is impossible (E-E mode is possible).
Although picture record is possible, color does not appear in PAL or NTSC mode (E-E mode is possible).
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
Is luminance signal (approx. 0.5Vp-p)
input to the pin(19) of IC201?
input to the pin(19) of IC201?
Is luminance signal (approx. 0.3Vp-p)
input to the pin(42) of IC201?
input to the pin(42) of IC201?
Is luminance signal (approx. 0.5Vp-p)
input to the pin(26) of IC201?
input to the pin(26) of IC201?
Is luminance signal (approx. 0.5Vp-p)
output from the pin(39) of IC201?
output from the pin(39) of IC201?
Is luminance signal (approx. 0.5Vp-p)
input to the pin(23) of IC201?
input to the pin(23) of IC201?
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
Is luminance signal (approx. 0.5Vp-p) input
and output to the pins(13) and (14) of
IC201, respectively?
and output to the pins(13) and (14) of
IC201, respectively?
Check between the pins(18) and (19)
of IC201. (Check C206.)
of IC201. (Check C206.)
Check between the pins(21) and (42)
of IC201. (Check C208.)
of IC201. (Check C208.)
Check between the pins(60) and (46)
of IC201. (Check C512.)
of IC201. (Check C512.)
Check between pins(58) and (35) of
IC201. (Check C515.)
IC201. (Check C515.)
Check between the pins(39) and (26)
of IC201. (Check C212.)
of IC201. (Check C212.)
Check between the pins(24) and (23)
of IC201. (Check C210.)
of IC201. (Check C210.)
Is voltage 5V applied to the CCD section power
terminal pin(36) of IC201?
terminal pin(36) of IC201?
Is CCD control voltage
(approx. 0V<PAL/MESECAM mode>,
(approx. 0V<PAL/MESECAM mode>,
5.0V<NTSC mode>
applied normally to the pin(37) from the
pin(57) of IC201?
Is clock signal
(approx. 8.86 MHz<PAL mode>,
pin(57) of IC201?
Is clock signal
(approx. 8.86 MHz<PAL mode>,
7.16 MHz<NTSC mode>
/0.5Vp-p) for CCD applied normally to the
pin(44) from the pin(69) of IC201?
pin(44) from the pin(69) of IC201?
Check the pins(13) and (14) of IC201
peripheral circuit. (Check R201, R202,
C203)
peripheral circuit. (Check R201, R202,
C203)
SP mode: Is there record FM signal (approx. 20mVp-p) output to the pins(88), (89) (SP1) and pins(86), (87) (SP2) of IC201?
Check or replace the cylinder.
Is PRE/REC Vcc 5V applied to pin(90) of IC201?
Is voltage 5V applied to the chroma section
power terminal at pin(61) of IC201?
power terminal at pin(61) of IC201?
Is chroma signal (approx. 143mVp-p/
burst) input into the pin(46) of IC201?
burst) input into the pin(46) of IC201?
Is chroma signal (approx. 180mVp-p/
burst) input in the pin(58) of IC201?
burst) input in the pin(58) of IC201?
Check peripheral of pin(61) of IC201
and PC 5V line.
and PC 5V line.
<For NTSC mode.>
Check whether the pins(73) and (71) of
IC201 oscillate 3.58MHz?
Check whether the pins(73) and (71) of
IC201 oscillate 3.58MHz?
<For PAL/MESECAM mode.>
Check whether the pins(73) and (75) of
IC201 oscillate 4.43MHz?
Check whether the pins(73) and (75) of
IC201 oscillate 4.43MHz?
Is chroma signal (approx. 180mVp-p/
burst) output to the pin(35) of IC201?
burst) output to the pin(35) of IC201?
FLOW CHART NO.20 RECORDING MODE TROUBLESHOOTING
YES
<For NTSC mode.>
Check peripheral parts of X501.
Check peripheral parts of X501.
<For PAL/MESECAM mode.>
Check peripheral parts of X502.
Check peripheral parts of X502.
48
VC-MH705HM/LM
VC-MH815HM/LM,MH85HM
VC-MH715HM,MH835HM
YES
YES
NO
NO
FLOW CHART NO.21 Hi-Fi SOUND MODE TROUBLESHOOTING(1)
Check line ranging from pins (31),(30) of
IC1701 (NICAM/GR), to the each input
terminal of IC2501.
IC1701 (NICAM/GR), to the each input
terminal of IC2501.
Check PC 5V and Hi-Fi 9V lines.
Is the supply voltage of PC 5V fed to pins(24),
(40) and 9V fed to pin (58) of IC651?
(40) and 9V fed to pin (58) of IC651?
No Hi-Fi E-E sound heard
Is there audio signal inputted at each input
terminal as shown in table?
terminal as shown in table?
Tuner input terminal.
IC2501 IC2501
pin(16) pin(15)
Decoder signal input
terminal.
terminal.
Check line ranging from pins (39),(40) of
IC2501 (decoder circuit) or audio input
terminal to the each input
terminal of IC651.
IC2501 (decoder circuit) or audio input
terminal to the each input
terminal of IC651.
Are there the serial data and clock at pins
(42) and (43) of IC651?
(42) and (43) of IC651?
Check line between pins (42),(43) of IC651
and pins (21),(27) of IC701?
and pins (21),(27) of IC701?
Check line between pins (57)and (53) of
IC651.
IC651.
Is there audio signal outputted at pin (57)
of IC651?
of IC651?
Is there audio signal outputted at pins (5),
(53) of IC651?
(53) of IC651?
YES
NO
NO
Is there audio signal inputted at each input
terminal of IC201 as shown in table?
terminal of IC201 as shown in table?
U/V tuner audio input terminal. pin(9)
Aux input terminal pin(8)
Is there audio signal outputted at pins (11),
of IC201?
of IC201?
Is there audio signal outputted at pin (62)
of IC651?
of IC651?
NO
NO
NO
NO
NO
Check line ranging from A-out pin (21),of
TU101.
TU101.
Check line ranging from pin (61) of IC651.
Line output terminal : Is there audio signal outputted at pins (59) and (53) of IC651?
RF output terminal : Is there audio signal outputted at pin(59) of IC651?
RF output terminal : Is there audio signal outputted at pin(59) of IC651?
Replace IC201.
Is there "L" level at pin(99) of IC201?.
Check line between pin (36) of IC651 and
pin(81) of IC701.
pin(81) of IC701.
Check line between pin (11) of IC201 and
pin (62) of IC651
pin (62) of IC651
YES
NO
Is there "L" level at pin(8) of IC651?.
Check line between pin (8) of IC651 and
pin (21) of IC701
pin (21) of IC701
Replace IC651.
YES
YES
YES
YES
YES
NO
NO
Line output terminal
Check line ranging from pins (59) and (53) of IC651 to pins (2) and (1) of IC2501.
Check line ranging from pins (59) and (53) of IC651 to pins (2) and (1) of IC2501.
RF output terminal
Check line ranging from pin (59) of IC651 to the audio input terminal of tuner TU101.
Check line ranging from pin (59) of IC651 to the audio input terminal of tuner TU101.
<For Hi-Fi mode>
<For normal mode>
IC651 IC651
pin(14) pin(9)
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