Kenwood KAC 719 Service Manual

Page 1

fifiéié1 9 KENWOOD

SERVICE MANUAL

© 2000-3 PRINTED IN JAPAN
351-7600-00 (S) 3344

Dressing panel Heat sink
(A21-4014-03) (F01-1627-01)
lfi n n
O - O
D D © c
C i
E
O im
E v~
B :3
R
Z 8"
3
m
I I I 3
D X © c
O O

Fuse Screw terminal Screw terminal Screw terminal

(F52-0015-05) board board board
(E70-0820-05) (E70-0818-05) (E70-0808-05)

Pin jack Screw terminal
(E63-0834-05) board
(E70-0824-05)

I I 0
Accessory Screw set Accessory (E type only) 'W/v
(wo1-1515-05) (N99-1587-05) (wo1-o797-05) I.

Page 2

KAC-71 9
CIRCUIT DESCRIPTION

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 head 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-INN, the DC component in the SP output
turns 038 ON through D32 and R158.

When a voltage is applied to the P-CON pin under this condition, 045 is

turned ON via R188, positive feedback is applied by combination of Q45 and
Q46, Q45 and 046 are held at ON, so the voltage at point (A) is almost 0 V

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 0 V.

7-5V power control

to P»CON terminal

D32

from SPF-CON 4-D: Q38

R188

Q45

ADJUSTMENT

TUNER
INPUT OUTPUT ALIGNMENT
N° EM SETTINGS SETTINGS (gggfi'fiég) POINTS AL'GN FOR F'G-
Connect a cassette receiver or other receiver.
IDLE Connect a DC . After sufficient aging
1 CURRENT ' voltmeter to 0N3 voume ' 0 VR3 adjust to 2mV (a)