Kenwood RC 2000 Service Manual

Page 1

EETTZROéEéo KENWOOD

SERVICE MANUAL

© 2001 -2 PRINTED IN JAPAN
851-8571-00 (N) 697

Modular cable DC cord Angle Trunk cable
IE30-3409-05I (E30-3406-05) (A13-0635-03) (E30-3407-05)

Speaker assy Control panel Spacer Trunk cable
(T19-01IB-05I IJ30-052l-04) x 2 IE30-3408-05I
CONTENTS

CIRCUIT DESCRIPTION ......... 2 PACKING ................................................... 7
SEMICONDUCTOR DATA ........................ 3 PC BOARD VIEWS
DESCRIPTION OF COMPONENTS .......... 4 DISPLAY UNIT (X54-3290-00I .............. 9
TERMINAL FUNCTION ............................. 4 SCHEMATIC DIAGRAM .......................... 13
PARTS LIST ............................................... 5 BLOCK DIAGRAM ................................... 15

EXPLODED VIEW ...................................... 6 SPECIFICATIONS ................. BACK COVER

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RC-2000

CIRCUIT DESCRIPTION

Panel Section (LCD ASSY : 338-0829-05)

The panel section controls serial communications with
the main unit control section, the key input circuit, the dis-
piay circuit, and the dimmer circuit through the microproces-
sor (IC4).

I Serial communications circuit
A buffer amp is inserted in order to protect the micropro-
cessor ports.

I Key, Volume input circuit

Circuits to operate the panel section keys are connected
to each microprocessor port. The PSW key is pulled up and
the other keys are pulled up with software within the micro-
processor. Rotary encoder operating circuits are connected
directly to the microprocessor. The controi divides the
power suppiy voitage, reads the A/D port of the micropro-
cessor, and transfers that data to the main unit.

I Display circuit

Display section is a 188 X 54Adot fuilldot matrix LCD con
trolled by two LCD. As shown is Figure l, the master 1C
(1C2) side is connected to 22 common dots and 88 segment
dots and the siave IC ilCl) side is connected to 33 common
dots and 100 segment dots. The LCD drive voltage is ob-
tained by raising the power supply voltage (5V) within the IC.

22

COM LCD
188 X 54 (dot) 33
COM

88

SEG

LCD LCD

Driver Driver
|C2 |C1

@@

Microprocessor
IC4

X547329

Fig. 1 Display circuit

I Dimmer circuit

The dimmer circuit switches the lamp brightness to one
of tour ieveis or OFF (See tablel ). The current flowing to the
LEDs is varied by selecting resistors from R8 to R14.

Dimmer ievel DIM O DIM l DIM 2 DIM 3
l H L L L
L H

2 L
3 L H
4 L L L

L

L
L
H
OFF L L L

Table 1 Port logic

ICA
Microprocessor

LCD ASSY

R15 9v

D|M3 08
R14

R11

D|M2 07
R12
own W
H9
Q4 05
R10
H8
DIMO
Q

Fig.2 Dimmer circuit

D30

R42