Sharp 27DV-S100 Service Manual page 64

No supply and take-up
reel pulse output.
Insert a cassette tape and
call the FF or REW mode.
Are pulses coming out of Check the reel sensors for stain
NO
and poor positioning. Check the
the supply reel sensor
clearance between the mechanism
(D7006) and take-up reel
and main PWB. Replace the reel
sensor (D7007)?
sensor(s) as required.
YES
Check the lines between
the reel sensors and pins
(3)/(2) of IC2001.
Drum servo malfunction.
Are there the reference
NO
Check X7001, C7007 and
signals (14MHz) at pins
C7008 for malfunction.
(37) and (38) of IC2001?
YES
Does the servo malfunction in Is there the composite
YES
the REC mode alone? (Make sync signal at pin (50) of
recording and playback. Does IC2001?
the switching point appear
onscreen and slowly move?)
NO
NO
Go to Flowchart No. 10
Is there the H.SW.P. signal
"No H.SW.P. output signal".
at TP3302?
YES
NO
Does the PC12V line
Check the PC12V line.
function?
YES
Does the duty ratio of the
drum error output at pins
NO
(32) and (34) of IC2001 Check IC2001 and
change according to the replace as required.
rpm (by gently pressing on
the drum motor)?
YES
Check the connection
between pins (32)/(34) of
IC2001 and pin (2) of
IC7006, as well as the
connection between IC7006
and drum motor. Replace
the drum motor as required.
FLOW CHART No. 2-11
FLOW CHART No. 2-12
Check the line
NO
between pin (52) of
IC2201 and pin (50) of
IC2001.
YES
Capstan servo
malfunction.
Are there the reference
Check X7001, C7007
NO
signals (14MHz) at pins
and C7008 for
(37) and (38) of IC2001?
malfunction.
YES
Go to Flowchart No. 12
NO
Does the drum servo
"Drum servo
function?
malfunction".
YES
Make recording on a Is there the playback
NO
tape with a well- control signal at pin (76)
adjusted set, and play of IC2001 during the play
of the recorded tape?
back the recording.
YES
Are there the record
control signals at pins Is there the specified
(74) and (75) of IC2001 capstan FG signal at
in the REC mode? pin (67) of IC2001?
YES
Are there the record
Does the duty ratio of
control signals at pins
the capstan error
(5) and (6) of connector
output at pins (31) and
AA?
(33) of IC2001 change
according to the rpm
YES
(by gently pressing on
Check the connection
the drum motor)?
between connectors
AA and MH. Check the
A/C head for height,
Does the voltage at pin
stain, etc.
(4) of connector AC
change according to
the rpm?
Replace the A/C head.
Check the connection
between connectors
Check the record
AC and MC. Replace
control signal line.
NO
the capstan motor.
Check IC2001 and
replace as required.
NO
Check IC2001 and
replace as required.
FLOW CHART No. 2-13
Check the connection
between connectors
AA and MH. Check the
NO
A/C head for stain,
height, breakage, etc.
Replace as required.
YES
YES
Is there the specified
NO
capstan FG signal at
pin (6) of connector
NO
AC?
YES YES
NO
Check IC2001 and
replace as required.
Check the line
YES
between pins
(31)/(33) of IC2001
NO
and pin (4) of
connector AC.
Check the line
YES
YES
between pin (6) of
connector AC and pin
(67) of IC2001.
Check the
connection between NO
connectors AC and
MC. Replace the
capstan motor.
YES Check the line YES
between pins (5)/(6)
of connector AA and
pins (74)/(75) of
IC2001.