Sharp 13VT-CL10, Service Manual, Page: 46 / 106

46
13VT
-L200
TAKE-UP REEL PULSE GENERATOR TROUBLESHOOTING FLOW CHART NO.1-7
HEAD SWITCHING PULSE TROUBLESHOOTING FLOW CHART NO.1-8
FLOW CHART NO.1-9
No reel sensor pulse appears.
No head switching pulse.
YES
NO
NO
NO
NO
NO
YES
YES
YES
Check the AT12V line.
Insert the cassette, and
put the unit in FF or REW
mode.
Replace the take
up/supply reel sensors
D7702/D7703.
Check the harness AD-
ME and the drum motor
unit.
Check pin (18) of IC7701
and signal line of head
switching pulse.
Check all the way up to
pins (86) and (87) of
IC7701.
Check between the ME socket
and pin (78) of IC7701, and
between the ME socket and pin
(76) of IC7701.
YES
YES
YES
NO
NO
NO
DRUM MOTOR TROUBLESHOOTING
The drum motor fails to run.
Is the voltage more than about
2.6V applied at pin (1) of ME
connector.
Check between the ME
connector and all the way up to
pin (86) of IC7701.
Is 5V at pin (7) of ME connector?
Check/replace the drum motor.
Is 12V at pin (4) of ME connector?
Check the AT 5V line.
NO
NO
NO
YES
YES
YES
Check or replace IC7701.
The drum motor runs only for a few seconds.
Check pin (76) of IC7701.
Check the drum motor.
Are there the take
up/supply reel pulses at
the collectors of
D7702/D7703.
Are the drum PG and
drum FG signal inputted
to pins (86) and (87) of
IC7701, respectively?
Are there the drum PG
and drum FG Signals at
pins (3) and (5) of
connector AD?
Check between D7702
and pin (80) of IC7701,
between D7703 and pin
(79) of IC7701.
Is the drum motor
rotating?
Is drum PG signal at pin (86) of
IC7701?
Is drum PG signal at pin (5) of
ME connector?
IS H.SW. pulse at pin (18) of
IC7701?
See FLOW CHART NO.
1-9.
4.2
4.4
0
0
D-PG
D-FG
about
4.5Vp-p