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testing.
(10) An external test video input can be applied to modulator channel 1
for testing.
(11) The VMU contains back-up power to keep its CPU card assembly in
operation for a minimum of 200 ms during system power interruption.
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Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
POWER
COMBINER
POWER
COMBINER
POWER
COMBINER
TEST VIDEO
VIDEO CH1
VIDEO CH2
VIDEO CH3
VIDEO CH4
VIDEO CH5
VIDEO CH6
VIDEO CH7
VIDEO CH8
VIDEO CH9
VIDEO CH10
VIDEO CH11
VIDEO CH12
TG CONT
RL CONT
TG CONT
RL CONT
+8V
-9V
POWER
COMBINER
RF
AMPLIFIER
MODULATED
RF VIDEO OUTPUTS
115 VAC
400 Hz
INPUT
RS-232C
DATA OUT
DATA IN
DATA RTN
DT (DATA)
CK (CLOCK)
LD (LOCK DETECT)
VSG
1
2
3
4
CH2
CH3
CH4
CH5
CH6
CH7
CH8
CH9
CH10
CH11
CH12
CH1
MODULATOR
POWER
COMBINER
POWER
DIVIDER
MICROCONTROLLER
PC (PWR CONTROL)
+24V
POWER
SUPPLY
+32V
FUNCTIONAL BLOCK DIAGRAM OF VIDEO MODULATOR UNIT
Figure 3
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Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
4. Circuit Operation
This subsection gives description of the circuit operation of the video
modulator unit (VMU). Refer to Figure 3 for the functional block diagram of
the VMU. The printed circuit card assemblies that are installed in the VMU
are as follows:
DESIGNATION FULL NAME QUANTITY
A1 card CPU card assembly 1
A2 card Modulator card assembly 12
A3 card RF power card assembly 1
A4 card Power card assembly 1
A5 card Mother card assembly 1
A6 card Fuse card assembly 1
A7 card Connector card assembly 1
A8 card Video signal generator card assembly 1
A. Equipment Designators
We usually use the designations only as the names of the above printed
circuit card assemblies.
The card designation (A1, A2, A3, etc.) is a part (prefix) of the
equipment designators of the card-installed electronic parts to correctly
identify them (e.g., A1IC110 and A2F201).
For electronic parts such as resistors, capacitors, transistors and
diodes, we usually use only their equipment designators as their names.
For an IC device, we will use its full name only at the first instance
and in parentheses after its equipment designator.
B. Refer to the wiring and schematic diagrams given at the END of the
TESTING AND FAULT ISOLATION - PART 1 section for full circuit data.
Page 10
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
C. CPU Card Assembly (A1)
(1) The A1 card does the functions given below:
(a) It programs the phase-locked loop (PLL) on each modulator card
to the preset frequency.
(b) It monitors each modulator card for the presence of a fault.
(c) In the event of a modulator card fault, it stops the RF output
of that modulator card.
(d) It makes data communication with the VSCU through its RS-232C
interface.
(e) It makes selection of the video input (video channel 1 or test
video) to modulator channel 1.
(f) It makes selection of the video input (video channel 2 or
internal video) to modulator channel 2. The internal video is a
monochrome video signal for white raster and is for BITE
testing.
(2) A1IC102 is an 8-bit microcontroller with a 7744 byte PROM and a 304
byte RAM. A1IC103 is a 64x16 bit EEPROM which contains the
frequency data for each A2 card.
(3) If the power to the VMU is stopped, A1IC102 will reload the
frequency data from A1IC103 when power is re-applied.
(4) DT01 thru DT12 outputs are the data signals to each A2 card, and
CK01 thru CK12 outputs are the clock signals to each A2 card.
A1IC102 programs the PLL frequency synthesizer on the A2 cards one
after the other with the data and clock signals. A1IC102 uses
A1IC107 and A1IC108 (3-to-8 line decoders) to apply the clock signal
to one A2 card at a time. The data signal is applied through
A1IC105 and A1IC106 (hex inverters) to all A2 cards, but the A2 card
does not accept the data signal without the clock signal.
(5) The RL CONT signal goes to A5RL1 (an electromagnetic relay on the A5
card). This signal controls the video input to the A2 card that
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COMPONENT MAINTENANCE MANUAL Video Modulator Unit (VMU)(18)
