13VT-K100/150
13VT-CK10
45
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