Sony SIU-100 Service Manual page 87

(4) Operation of external connector
The IN connector (CN1500) of the external sync signal is
for uses of the both word clock and the video signal. Its
internal paths are switched with the slide switch (S1500).
The video or word synchronization depends the menu
operation. Therefore, if the menu is set to the video
synchronization and the switch is set to the word, it is
simply considered that there is no video signal input.
The THRU connector is the loop through connector. It
always outputs the input signal as it is (in both video and
word).
The THRU connector has a switch. When the THRU
connector is connected with the BNC connector, the 75 Z
terminal of the IN connector is released.
The WORD OUT connector always outputs the word clock
synchronized with the internal operation.
2. CP-383 Board
The CP-383 board is the user interface on the front panel.
It does not have a function like the CPU. It operates
passively according to the signal from the CPU-353 board
(through the MB-983 board).
IC2001, 2002:
The two PLDs decodes the address at the CPU bus-access,
stores the LED display data, and generates the timinings to
light the LEDs.
Displaying LCD (ND2101):
The LCD unit has the display control function. The data to
be displayed is written from the CPU through IC2104/
2105.
Lighting LEDs:
The LEDs on the CP-383 and LED-399 boards are con-
trolled by IC2001 and 2002. The CPU writes the LED data
to be lit into IC2001 and 2002 by the bus-access.
IC2001 and 2002 stores the data, and lights the LED while
generating the dynamic scan-timing.
Recognizing buttons and neumeric keypad:
By receiving the read-access from the CPU, the CP-383
board outputs the condition if a button or the numeric pad
is pressed. This timing signal is generated by IC2001.
Headphone monitor output:
The headphone monitor output is sent from the CPU-353
board to the CP-383 board as the digital signal, and it
receives the DA conversion on the CP-383 board to be
output to the HP board.
SIU-100/100T
3. MB-983 Board
The MB-983 board passes the power and all the siganls
between the boards. The MB-983 board also has the
following functions:
. +5 V power ripple filter
The LC filter, whitch is composed of L3001, C3003,
C3004, C3005, and C3006, reduces the ripple of +5 V
power.
. Power generation for fan
From the +15 V power, IC3001 generates the +9 V
power, whitch is for driving of right-side fan. Although
this fan normally drives with +12 V power, it drives
with +9 V (within specification) for the noise reduction.
4. IF-895 Board
. The IF-895 board passes the power from the power unit.
It supplies the AC power from the AC INLET to the
power unit.
It also supplies the +5 V and ± 15 V powers output from
the power unit to the MB-983 board.
. The IF-895 board mixes the DC powers output from the
power units.
It mixes the +5 V and ± 15 V powers output from the
power units A and B with the diode to supply to the MB-
983 board.
. Generating +3.3 V power
From the +5 V power, the IF-895 board generates the
+3.3 V power to supply to the MB-983 board.
. Detecting DC power voltage (IC6101, 6201, 6104, 6204)
The IF-895 detects the voltage decrease of the +5 V and
+15 V lines, and notifies it to the CPU-353 board
through the MB-983 board.
5. Power Unit (Power Assembly A-8346-000-A)
(1) PS-640 Board
Function: Generates the DC +5 V and DC ± 15 V powers
from the AC power (100-240 V).
n
The individual parts on the PS-640 board are not supplied.
If any trouble occurs on the board, replace the PC-640
mounted circuit board.
Mounted circuit board PS-640 (Part No. A-8346-010-A)
(2) LED-400 Board
Function: Lights while the power supply (PS-640 board)
is in operation.
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