2
KAC-819
ADJUSTMENT
CIRCUIT DESCRIPTION
No.
ITEM
FIG.
INPUT
SETTINGS
OUTPUT
SETTINGS
TUNER
(RECEIVER)
SETTINGS
ALIGNMENT
POINTS
ALIGN FOR
1
IDEL
CURRENT
-
-
Connect a DC
voltmeter to CN3
Volume : 0
VR3
After sufficient aging
adjust to 2mV
Connect a cassette receiver or other receiver.
D29
Q46
Q45
10u35
+
R188
100K
R158
7.5V
to P-CON terminal
power control
from SP-P-CON
4.7K
3.3K
D32
Q38
A
SP P-CON Switching Circuit
When the SP output from the head unit is connected to SP IN, the power can be switched ON/OFF based on the
DC voltage of the SP output. However, As certain haed unit models output DC permanently or generate a click
during switching OFF, it is required to provide the capability of previous P-CON switching. A circuit which can
perform the switching without using a switch is described below.
This circuit performs switching by inhibiting the operation of the S-P-CON circuit when a voltage is applied to the
P-CON pin.
Circuit operation description
When the head unit is connected to SP-IN, the DC component in the SP output turns Q38 ON through D32 and
R158.
When a voltage is applied to the P-CON pin under this condition, Q45 is turned ON via R188, positive feedback is
applied by combination of Q45 and Q46, Q45 and Q46 are held at ON, so the voltage at point (A) is almost 0V and
the SP-P-CON circuit is not activated.
This circuit holds the ON status while the DC voltage from SP is present.
Therefore, in this condition, the P-CON circuit continues functioning. To cancel the functioning, the voltage at the
SP-IN pin should go 0V.
