Mpu Board - Ikegami HTM-1550R Service Manual

2-2 MPU BOARD
(1) Outline
lb.is board performs all controls of the monitor by the MPU and DC
control It also generales various lest signals and marker signals.
(2) Circuit description
(a)
MPU
The JCS MPU QJD6303YF) is a 8-bit CMOS microprocessor in-
corporaling a CPU, timer, RAM (256 bytes), SCI (serial communi-
cation inlerface). and I/O on a single chip.
The MPU operales by the program memorized in the external
EPROM IC7 (64 k bytes). Each data is memorized in the static
RAM !Cll (32 k bytes).
Even when tlie power is turned OFF, this RAM preserves dala
by
lhe lithium battery (BT!).
(b) 1/0
The 1/0 control between lhe modules MPU, FRONT PANEL,
CONlROL is pedonned by latching the dala bus with the address
decoder (ICl3, IC15, IC16, IC17, and IC97).
(c) RAM backup circuit
"The 32 k bytes static RAM (]Cll) memorizing
;;;c-
all digilal control dala should preserve data fur
C2 7
about 10 years using lhe lithium battery (811).
ICJ2 deleds lhe voltage of lhe battery used, and
cfuplays a message on lhesaeen when lhe voltage falls below 24V.
(d) Display generator and marker color control
The characler generator (IC25) operating by the HD and VD
is
con-
trolled by the data from the CPU, and outputs characler signals and
background signals of R, (\ and B.
The marker level is controlled according to the DC 1evel of VR 1.
The analog switch (IC29) is used to switch between lhe charader
signal and marker Jevel.
(e) DIA, S/H circuits
The low 8-bit and upper 8-bil dala are senl lo the RAM in two parts.
The 16-bil dala Jalched (IC36, IC37) is input lo the DIA converter
(IC38).
The data is sent continuously, and the analog multi-plexer (IC41,
IC42) work as a circuil lo divide the data.
Dy capacitors (C83 to 92) for this IC and hold lhe sample and hold
circuit are being composed.
(t) TEST, marker signal generator circuit
IC64 and IC65 are ICs for Pill. IC64 operates as a circuit gener-
ating lest signa1s, free-run HD and VD signa1s from lhe crystal
(27.MHzXl) clock. IC65 operates as a circuit generating HD sig-
nals lo be provided lo lhe PIL(IC56).
And also controls lhe ROM (IC74, IC75) storing lhe dala of the
TEST signaJ and marker signal
The EPROM IC75 memorizes data on lhe pattern of one line (64
bytes) in each ack:lre$. The acklft8i rontrol memoriz.es lhe memo ad-
dress data (vertical data).
For the marker signals and some test signals (CROSS HATCH,
CHARACTER), lhe data (8bils) output from IC75 is serial-parallel
convetled by IC76.
Other test signals are ana1og-o:mverted by IC78.
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(3) Adjustment procedure
(a) EL2: Elbit
SI: Dip switch
The initial setting of the type different peculiar (lag relation of the
monitor.
Q) The position of EU is set as follows for each type of monitor.
HTM:H1M1550R/2050R
CS:
H1M1550CS
8090:
80f)()SIRIFS
®
The position of SI is set as follows for each type of monitor.
PH-H:
JPN phosphor= ON (80f)()seriesonly)
EDU phosphor= OFF
PH-C: C phosphor= ON (80f)()series only)
EDU phosphor= OFF
CONV: To activate SOOJC CONV= ON
TYPE-I: TYPE-I (720Pcompatible) = ON
FT: Adjustment mode= ON (Setting at shipment: OFF)
(b) VRl: MK LVL
VR6: 1EST-S LVL
VR7:DALVL
Q) VRI is used to adjust the contrast Jevel of the marker.
Normally
sci
to the center.
@
Set MARKER Lo OFF, and internal "JEST signals to ON, and seled
lhe CROSS HATCH signal.
Adjust VR6 so Iha! lhe!evel ofTP24 becomes 1.0±0.01 Vp-p.
@ Select lhe WINDOW signal.
Adjust VR7 so that lhelevel ofTP24 becomes 1.28±0.01 Vp-p.
(c) VR2: 4: 3U-CONT
VR3: 16:9N-CONT
VR4: 16:9U-CONT
(D Input lhe SDlV WINDOW (100%) signal, and adjust lhe preset
CONTRAST level on lhe drawer so that lhe 4:3 NOR-SCAN be-
comes 120 cd/m
2 •
@ Adjust
VR2
so that lhe 4:3 UNDER-SCAN becomes 120 cd/m
2 •
@ Adjust VR3 so that the 16:9 NOR-SCAN becomes 120 cd/m 2 •
@
Adjust VR4 so Iha! lhe 16:9 UNDER-SCAN becomes 120 cd/m
2 •
*
For HTM-2050Rl, adjust all the above values to 100 cd/m
2
•
(d) L7
Adjust the screen display range of the chruacter.
(D Set the MENU screen to STATIJS and lhen set SHADOW.
Adjust L7 so that lhe charaders displayed are not in the shadow.
*
For HTM-1550Rl and HTM-2050Rl, adjust in lhe 720P mode.
(e) YRS: WIND LV
Adjusler for the 80/90 series. No adjustment is-required.