Sony Jumbotron JME-UA200, Service Manual

Page: 31 / 56

4-1(E) JME-UA200
Fig. 1 Block Diagram
SECTION 4
CIRCUIT DESCRIPTIONS
RXD0
TXD1
RXD1
RS1
CS1
MD0
ı
MD15
MA0
ı
MA19
DATA
ADDRESS
SYSTEM
CLOCK
X3
19.660MHz
LINE SELECT
GAIN
AMP
SENSOR
UNIT SENSOR
JME-US15L
SENSOR
CONTROL
IC50
DUAL
PORT
RAM
FLASH
MEMORY
SRAM
PROGRAM
ROM
LCD
MODUL
KEY
MATRIX
IC38, 39
IC52
IC54
IC51
IC35
LINE
RECEIVER
IC53
DRIVER/
RECEIVER
From UNIT
To PC
To UNIT
CLOCK
NTSC
CLOCK
PAL
X2
18.88MHz
X1
18.75MHz
IC2
IC4-10
COUNTER
ADR BLK
IC11,12 IC13,14
IC31,32 IC33 IC34
LINE
DRIVER
P/S
CONVERTER
10-10
SIGNAL
CONVERTER
IC40
MPU
GAIN SELECT
FILTER
AMP
4-1. SPG MODE
The MPU (IC40) reads the mode selected with the key
matrix, and writes video data corresponding to the mode
into the left side of dual port RAM (IC38, 39) every 1/60
second. On the other hand, the counters (IC4-10) are
rotated by the clock selected with the change-over switch
(IC2) to read out video data written by the MPU (IC40)
from the right side in the order of Jumbo Tron format.
For the synchronization, SYNC signal, EOF signal, and
line addresses are added, then they are coded by the 10-10
signal converter (IC31, 32). (To insulate the unit, the
signals are forced through the pulse transformer before
they are received, so that the 10-10 conversion is made to
remove adirect current component. Also, the transmission
error detection is executed.) The coded data are serial-
parallel converted (IC33) to be serial signals, then
transmitted to the unit by the differential line driver (IC34).
(By the amount of 32 dots in horizontal direction)
4-2. ADJUST MODE
Various codes for brightness adjustment or unit control are
transmitted with vertical sync part (483 blocks for NTSC,
or 580 blocks for PAL) after video data. Normally, non-
processing codes (NOP codes) are transmitted with these
blocks, but if the commandsfor brightness adjustment and
unit control are entered from the keyboard, the MPU
(IC40) writes the control codes indual port RAM (IC38,
39), and they are inserted into the control data blocks and
trans-mitted. (One command every 1/60 sec forNTSC, or
one command every 1/50 sec for PAL)