Sharp FO-DC635U, Service Manual

Page: 84 / 166

FO-DC635U
5 – 18
[5] Circuit description of operation panel PWB
1. Operational description
1) Operation panel PWB
The operation panel PWB includes the ten key scan circuit and the
LED lighting circuit.The LS145 is controlled through LD0~LD3 (4
bits) and ten key detection is performed. The HC174 is controlled
through LD0~LD5 (6 bits) to provide LED lighting information.
2) LCD (LM046QB1H01)
The COG uses the one-chip LCD driver IC to display 20 digits x 2
lines. The LCD display density is controlled with an external resis-
tor.
a) Scope of application
This specification applies to a positive diffusion type mono-
chrome dot matrix LCD module LM046QB1H01.
b) Structure and external shape
Structure: 320 x 240 monographic display module
This dot matrix LCD module consists of an LCD panel, a print
PWB mounting electrical parts, a TCP electrically connecting
these units and bezels fixing them mechanically.
2. Block diagram
TCP
PWB
LCD PANEL
(hard coating)
Bezel
Fig. 10 Module construction plan
Fig. 11
PLTSW
SEN[7:0]
LD[7:0]
LEDEN1
LEDEN2
YD
LP
XCK
M
DISP
D[3:0]
PAGE PLATE SW
KEY MATRIX(10 x 8)
LED PWB
LCD RELAY PWB
LCD
(320 x 240 DOTS LCD)
LS145
AHCT174
AHCT174
LD[3:0]
LD[5:0]
LD[5:0]
+5V
+5V
TH1
TH2
t¡
RT1