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(6) A2 Cards and Modulator Channels
The UUT contains twelve A2 cards that are interchangeable. Each A2
card contains one modulator channel. Their channel numbers are
given from their positions on the A5 card. They are as shown in
Figure 138.
FRONT
A1 CARD
CH12
CH11
CH10
CH9
CH8
CH7
CH6
CH5
A5CN19
A5CN18
A5CN17
A5CN16
A5CN15
A5CN14
A5CN13
A5CN12
A5CN11
A2 CARDS
CH4
CH3
CH2
CH1
A5CN9
A5CN8
A5CN7
A5CN6
A5CN5
A5CN10
A3 CARD
A4 CARD
LOCATION OF MODULATOR CHANNELS
Figure 138
We will use the designators "CH1" thru "CH12" to identify the
related A2 cards.
T&FI-2
Page 156
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
(7) Fault Isolation on A1 thru A4 Cards
(a) If the UUT is energized, use the procedure given below to
disconnect and connect the A1 thru A4 cards:
1 Click on the "USER CONFIG" button (ref. Figure 134).
2 Make sure that the user configuration values are shown in the
Frequency boxes.
3 Set the tester's POWER switch to OFF to de-energize the UUT.
The "COMMUNICATION ERROR" box will show in 10 or 20 seconds.
4 Disconnect and connect the cards as necessary.
5 Set the tester's POWER switch to ON, then click on the
"CONTINUE" button of the "COMMUNICATION ERROR" box.
6 You can continue the fault isolation after the user
configuration values are fully shown.
(b) For the A1, A2 and A4 cards, extension cards are available. Use
them to get access to the circuits on the A1, A2 and A4 cards.
(c) For the A3 card, disconnect the A2 cards as many as necessary to
get access to the rear side of the A3 card.
(d) You can interchange the A2 cards to find a defective A2 card.
For RD-AA5002-23 and RD-AA5002-25, before you do the functional
testing, make sure that 100-W input A2 cards are installed as
follows:
UUT POSITION OF 100-W INPUT A2 CARD
RD-AA5002-23 CH12 only
RD-AA5002-25 CH7 thru CH12
(e) Most of the modulator circuits on the A2 card are in the shield
cases. Remove the shield cases as necessary.
T&FI-2
Page 157
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
(8) Fault Isolation on A5 thru A8 Cards
(a) You can get access to the A5 and A8 cards if you remove the
bottom cover.
(b) For the A6 and A7 cards, do the fault isolation through
continuity check under the de-energized condition with the test
harness removed from the J1 connector.
(9) Parts Identification
For electronic parts, we usually use their equipment designators
only to identify them in the fault isolation data and procedures.
The card designation (A1 thru A8) is a part of the equipment
designators of the card-installed electronic parts for their correct
identification in the UUT (e.g., A1IC100, A3IC301 and A8IC501).
(10) Electrostatic discharges from your hands or tools can cause
permanent damage to most of the semiconductor devices on the printed
circuit card assemblies. Obey the general precautions given below
to prevent such damages:
· Do the disassembly and assembly work on a grounded conductive
surface.
· Put on a conductive wrist-strap that is grounded.
· Touch your tool to the ground (grounded metal structure, etc.)
before you use it.
· Use a tip-grounded soldering iron.
· Put the removed printed circuit board assembly on a grounded
conductive surface.
(11) The logic signal levels are as follows:
SIGNAL CONDITION SIGNAL VOLTAGE LEVEL (TO GROUND)
H (High) Approximately the positive supply voltage.
L (Low) Approximately the ground potential (0 V).
T&FI-2
Page 158
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
D. Fault Isolation Data
The fault isolation data is given below as a table (Fault Isolation
Table), for which we use the assumptions given below:
· The cause of malfunction is one, not two or more.
· The UUT was satisfactory in all checks and items until you found it
unsatisfactory.
The ITEM column of the Fault Isolation Table shows the paragraph
identification of the step or check in which the UUT was found
unsatisfactory.
The SYMPTOM column gives a specific type of problem that you possibly see
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COMPONENT MAINTENANCE MANUAL Video Modulator Unit (VMU)(75)
