Akai VS-2EGN - Page 37

The capstan motor FG pulses whose frequency is divided
by 16 is inverted at the inverter, and fed to IC1 pin@).
This signal is routed through the CTL PG AMP and the
REC/PB switch, output from pin(2), and fed to TRS.
This signal is subjected to. inversion, amplification,
shaping by TRS, and is then fed to IC7 pin (0.
2) 1/7 counter (Refer to Fig. 7-30)
1C7 2/2 is a 1/7 counter circuit.
During recording
The
1/16
capstan
motor
FG
pulses
shaped
by
TRS
are
fed to IC9 pind).
Since
IC9
pin
@
is
at
the
low
level
in
the
recording
mode, the iverted waveform of pin ® is output to IC9
pin (3). This output is fed to IC11 pin © as a com-
parison signal through R76,D10 and TR22.
(6) During playback
The CTL pulse reproduced at the CTL head is fed from
IC1_ pin ©, output from pin (2) through the CTL PB
AMP and REC/PB switch, and fed to TRS.
This CTL pulse is shaped at TRS, and fed to IC9 pin).
Afterwards in a similar way to the recording mode of
operation, the signal is fed to IC11 pin © as a com-
parison signal.
cTL
PULSE | 1
\ \
i \
1c9(Q) 1
!
‘
icii@®
i
i
!
RESET —+ 12v
1c7® SESS SoS SSeS aa i aa ee ov
i |
\ |
ov
a2
1c7@ I
© CUE or REVIEW mode (refer to Fig. 7-30)
Since CUE or REVIEW (hgih level) is applied to IC9 pin
, IC9 pin Q)is at the high level. ‘Accordingly,IC 9 pin
becomes low level, and D10 is cut off.
On the other hand, IC8:pin (2) is at the low level, as
known from the examination of the state of the RESET
terminal (pin (3) ) of IC7 2/2.
That is, CUE or REVIEW (‘H’) is fed to IC9 pins(8) and
Fig. 7-33 REC/PB mode timing chart
O} inverted and supplied from IC9 pin @.
Since the AND circuit composed of D6, and 8 and R72
is connected to IC8 pin @, the RESET pulse is output
to IC7 pin @. The 7 times rate CTL signal reproduc-
ed at the CTL head is inverted at TRS, fed to IC7 pin
@O , counted down to 1/7, and output from pin &
This pulse is differentiated at R74, C46, R75, D9, and
R83, and fed to IC11 pin ® as a comparison signal.
CAPSTAN MOTOR
i
1
|
\
COMPARISON
SIGNAL
a
ic
©
|
1
1
1
i
1
Hl
f
|
eee
|
1 {
i ! 1 I 1 {
if 1 1 I
34
Service Manual VS-2EGN
' i ' t i
if 1 i) 1 i} 1 i
1 1 i
Fig. 7-34 1/7 counter timing chart (CUE or REVIEW mode)