Sharp VC-M313 (serv.man14) Service Manual ▷ View online
41
FLOW CHART NO.12 CAPSTAN MOTOR TROUBLESHOOTING
The capstan motor fails to run.
Is the voltage more than about 2.6V
DC given out of pin(59) of IC701?
Check IC701.
NO
NO
NO
NO
NO
YES
YES
YES
YES
Is the supply voltage of 5V fed to
pin(8) of AC connector?
Check PC 5V line.
Is the voltage more than 2.6V DC
sent in pin(4) of AC connector?
Check line between the AC connector
and pin(59) of IC701?
Is the voltage of pin(3) of AC
connector 1.6~2.7V?
Check line between the pin(60) of
IC701 and pin(3) of AC connector.
Is the supply voltage of 12V/20V fed
to pin(5) of AC connector?
YES
Replace capstan motor.
Check MOTOR Vcc line and motor
voltage selector circuit.
(Q9903, 9904, 9909, 9910)
FLOW CHART NO.13 DRUM MOTOR TROUBLESHOOTING(1)
The drum motor fails to run.
Is the voltage more than about 2.6V
DC given out of pin(58) of IC701?
Check IC701.
NO
NO
NO
YES
YES
Check PC 5V and line and pin(9)
of IC701.
Is the supply voltage of 5V fed to
pins(25) and (2) of IC702?
Is the voltage more than about 2.6V
DC given out of pin(29) of IC702?
Check line between pin(58) of IC701
and pin(29) of IC702.
NO
YES
YES
Is the supply voltage of 12V fed to
pin(20) of IC702?
Replace drum motor.
Check M 12V line.
FLOW CHART NO.14 DRUM MOTOR TROUBLESHOOTING(2)
The drum motor runs only for a few seconds.
Replace IC702.
Check peripheral circuit of pins(4),
(5), (6) and (7) of IC702.
Is drum PG signal given out from the
pin(8) of IC702?
Is drum PG signal fed to pin(66) of
IC701?
Check line between pin(8) of IC702
and pin(66) of IC701.
Is head switching pulse sent out
from the pin(23) of IC701?
Check IC701.
Replace IC701.
NO
Check drum motor.
YES
YES
YES
YES
NO
NO
NO
D-FG
about 5Vp-p
D-PG
about 5Vp-p
YES
NO
YES
YES
NO
NO
FLOW CHART NO.15 HEAD SWITCHING PULSE TROUBLESHOOTING.
No head switching pulse.
See FLOW CHART NO.13, 14
(DRUM MOTOR
TROUBLESHOOTING(1), (2))
Is the drum motor rotating?
Is the drum PG signal and drum
FG signal present on pins(66) and
(65) of IC701, respectively?
Replace IC701.
Check line between IC702 and
IC701.
Check peripheral circuit of IC702.
Are the drum PG signal and drum
FG signal present on pins (8), (9)
of IC702?
42
FLOW CHART NO.16 DRUM SERVO TROUBLESHOOTING
Drum servo does not function.
Check peripheral circuit of X703.
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(85)
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.
43
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 X703.
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?
44
FLOW CHART NO.18 E-E MODE TROUBLESHOOTING
No picture E-E signal.
NO
NO
NO
NO
NO
YES
YES
YES
YES
Is there picture signal inputted
in the pins(28), (30) and (31)
of IC201?
1For ext. input mode.
nCheck line between rear video input terminal and pin(30)<1-scart>
or pin(31)<2-scart> of IC201.
nCheck line front video input terminal and pin(28) of IC201.
2For U/V tuner mode.
nCheck line between video output terminal of tuner and pin(31) of
IC201.
Is the supply voltage of 5V
(Y-Vcc) fed to pin(12) of
IC201?
Check PC 5V line.
NO
Check line between pin(52) of
IC201, and pin(49) of IC701.
YES
YES
YES
Is there a picture signal
outputted in the emitter of
Q708?
Check peripheral circuit of
Q708.
NO
Check the line between Q708
and Q2801. <1-scart models>
Check the line between Q708
and IC2501. <2-scart models>
Is there Y/C serial data and
Y/C clock signal applied to
pins(63) and (62) of IC201?
Check line between pins(63),
(62) of IC201 and pins(56),
(57) of IC701.
NO
Is the supply voltage of 5V
(OSD-Vcc) fed to pin(51) of
IC701?
Replace IC201.
NO
Check PC 5V line.
Is there a picture signal
inputted in the base of
Q2801?<1-scart models>
Is there a picture signal
inputted in the pin(19) of
IC2501?<2-scart models>
YES
NO
Check peripheral circuit of
Q2801. <1-scart models>
Check peripheral circuit of
IC2501. <2-scart models>
Is there a picture signal
outputted in the emitter of
Q2801?<1-scart models>
YES
1Line output : Check the line between Q2801<1-scart models> or
IC2501<2-scart models> peripheral and output
terminal periphery.
2RF output : Check the line between Q708 peripheral and RF
video input terminal of tuner periphery.
Is there a picture signal
outputted in the pin(20) of
IC2501?<2-scart models>
Is there a picture signal
outputted in the pin(52) of
IC201?
Is there a picture signal
inputted in the pin(49) of
IC701?
Is there a picture signal
outputted in the pin(47) of
IC701?
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