Sharp VC-ME80HM Service Manual ▷ View online
41
VC-ME80GM
VC-ME80HM
VC-ME80HM
NO
NO
NO
FLOW CHART NO.9 CASSETTE CONTROL TROUBLESHOOTING(2)
A cassette tape is taken in, but ejected at once.
Does the start sensor pulse at pin(79)
of IC701 change from "L" to "H" level
when the cassette tape is loaded?
Check line between start sensor and
pin(79) of IC701.
Does the end sensor pulse at pin(85)
of IC701 change from "L" to "H" level
when the cassette tape is loaded?
Check line between end sensor and
pin(85) of IC701.
Does the master cam mode shifter
operate normally when he cassette
tape is loaded?
Check line between cam switch and
IC701.
Replace IC701.
YES
YES
YES
FLOW CHART NO.10 LOADING MOTOR AND EJECT TROUBLESHOOTING
The cassette tape fails to come out.
Does the capstan motor start when
the EJECT button is pressed?
See FLOW CHART NO.12 CAPSTAN
MOTOR TROUBLESHOOTING
Does the take-up reel disk turn when
the capstan motor is running?
Check line between take-up reel
sensor and pin(2) of IC701.
Is a "H" level applied at pin(10) of
IC702 when a reel pulse has been
inputted?
Check line between pin(92) of IC701
and pin(10) of IC702.
Is the supply voltage of 12V fed to
pin(13) of IC702?
Is the voltage about 10V sent out
from pin(15) of IC702?
Check IC702.
Is the specified voltage applied at the
loading motor terminal?
Check line between IC702 and
loading motor.
Does the loading motor run?
Replace loading motor.
Replace cassette cam, gear, etc.
YES
YES
YES
Check M 12V lines.
NO
YES
NO
YES
YES
YES
NO
NO
NO
NO
NO
YES
YES
YES
NO
NO
NO
NO
FLOW CHART NO.11 SYSTEM CONTROL TROUBLESHOOTING
No power is turned on.
Check IC801 and IC701, and all the
way thru between them.
Are FIP clock pulses and FIP control ready pulses applied to pins (24), (23) and (22) of IC5001,
respectively?
Does power control (H) signal at
pin(94) of IC701 change from "L" to
"H" level?
Check IC701.
Does the base voltage of Q974
change from about 9.3V to 10V?
Check line between Q970, Q974,
Q977 and IC701.
Is voltage of 9V sent out from the
emitter of Q974 transistor?
Check peripheral circuit of Q974 and
the line between D923 and correcter
of Q974.
YES
YES
YES
NO
NO
Does the base voltage of Q971
change from about 5.5V to 6.2V?
Check line between emitter of Q974
and base of Q971.
Is voltage of 5V sent out from the
emitter of Q971 transistor?
Check peripheral circuit of Q971
and AT 5V line.
Check peripheral circuit for poor
soldering.
42
VC-ME80GM
VC-ME80HM
VC-ME80HM
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
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.
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?
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.
(Q952, Q954, Q956, Q957)
43
VC-ME80GM
VC-ME80HM
VC-ME80HM
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(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.
44
VC-ME80GM
VC-ME80HM
VC-ME80HM
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.
are 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?
Click on the first or last page to see other VC-ME80HM service manuals if exist.