Akai X-360

Recording Amplifier are decreased by the
Volume Control, and the COM Detector Card
input signal level is reduced accordingly.
When the signal level to the Recording Amplifier
is reduced to O VU, the conditions of the COM
Detector Card Transistors are again as indicated
in blue print in Figure 10, TR70-7 is cut off
and the Motor stops.
TR70-5 and TR70-6 insure that the Motor
“stops immediately when signal level reaches
O VU. ,
Since the Comput-O-Matic Motor operates
only in the direction for decreasing the signal
level (with input signals applied), if the input
signal becomes too low, Comput-O-Matic
recording level must be reset by depressing the
Set Button “OFF” and then back “ON”. At
this time, Relay MH2PM-0 is cut off (as
described in (a) above). Thus, the Volume
Control rotates toward the upper limit, auto-
matically stopping when the VU Meter Indi-
cator Needle registers O VU.
c)
DM Detector
The DM Detector Circuit automatically detects the
quality of recorded sound, and when Playback level
deteriorates during recording and playback (due to
dirt, magnetic oxide, etc. on the Recording or
TR7I-3S TRI
TR7I=t TRI RII a
2SC650(B) 2SCE50(3} 25C4HSLE(B) ZSC45ELGIE) BBs
— = a _
| it
ve bse six
seis = SS -7 HIS ERG
Sf | ute Ree Ko Fe
tif e7i~
9KHz BIAS TRAP
PE AF
F.8. HEAD
E
“K.
&
|
athe
tw
sssssss5 yw
ia
i
Fig. 11]
Playback Heads), the D.M. Indicator Lamp lights.
9 KHz is used as a drive signal for the DM Detector
Circuit. The DM Detector Card is connected to the
Ist Stage of the Playback Amplifier, as shown in
Figure 11.
The Ist through the Sth Stages of the DM Detector
Circuit serve as a 9 KHz Filter Amplifier. A 90 KHz
Bias Trap Circuit is inserted between the 4th and
5th Stages to prevent operational error from
Magnetic Bias Flux during recording.
The circuitry from the 6th through the 9th Stages
serve aS switching circuits. Presence of the 9 KHz
component in Playback output signals results in the
condition printed in blue in Figure 11, Transistor
TR71-9 stops functioning and the DM Indicator
Lamp is extinguished. If the Playback Head is dirty
and no 9 KHz component is included in the
playback output signals, conditions will be as
indicated in red print in Figure 11, TR1-9 will be
actuated (‘‘ON’’) and the Indicator Lamp will light.
Also, if the Recording Head is dirty during record-
ing and no 9 KHz component is included in the
playback output signals, the Lamp will light.
At 1-7/8 ips tape speed, power is cut to the DM
Detector by the Speed Selector Switch SW39-1,
thus DM Detector circuit won’t function. During
STOP, as there is no need for the Lamp, so power is
cut to the DM Detector Circuit by Microswitch
SW207.
“okHz INPUT* ON
NO SIGNAL ~~ OFF
swZzer
: PAY, LUEKIN
L
nie 609 oF
mpe7t | 2asoma a
r LAMP 1/50
ere
30