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COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
B. General Instructions for Fault Isolation
(1) DO NOT USE THE OSCILLOSCOPE FOR FAULT ISOLATION ON THE T1 AND T2
PRIMARY AND SECONDARY CIRCUITS. USE A DMM OR VOM FOR VOLTAGE
MEASUREMENTS ON THESE CIRCUITS.
The case and ground terminals of the oscilloscope are usually
grounded. If you touch the T1 or T2 primary circuit with the ground
clip of the oscilloscope, a primary short-circuit fault can occur.
The signal ground of the UUT connects to the chassis ground. If you
touch one of the T1 or T2 secondary windings with the ground clip of
the oscilloscope, a secondary short-circuit fault can occur.
(2) Use the oscilloscope to measure the DC and AC voltages and to
monitor the signal waveforms on the A1 thru A8 cards. The probe of
the oscilloscope must have a sharp point to go through the layer of
insulating compound.
(3) Signal Ground for Oscilloscope
The signal ground of the UUT connects to the chassis ground through
the A4 card and J1 connector. You can use a bare metal part of the
UUT as the signal ground for the oscilloscope.
(4) Refer to "D. Fault Isolation Data" to find the possible problem area
and/or fault isolation procedure.
(5) Card Identification
For the printed circuit card assemblies installed in the UUT, we use
their designations only as their names. Refer to the table below.
DESIGNATION FULL NAME
A1 card CPU card assembly
A2 card Modulator card assembly
A3 card RF power card assembly
A4 card Power card assembly
A5 card Mother card assembly
A6 card Fuse card assembly
A7 card Connector card assembly
A8 card Video signal generator card assembly
There are twelve A2 cards installed in the UUT. Refer to (6) below
for their special identification.
Page 138.02
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
(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 103G.
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 103G
We will use the designators "CH1" thru "CH12" to identify the
related A2 cards.
(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 Push the F9 key (NEW) and then the Enter key. The program's
first screen (Figure 103B) will come back.
2 Set the tester's POWER switch to OFF to de-energize the UUT.
3 Disconnect and connect the cards as necessary.
Page 138.03
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
4 Set the tester's POWER switch to ON to energize the UUT.
5 Put in the UUT's part number and serial number as given in
5.A. and start the program.
6 You can continue the fault isolation after you see the main
screen as shown in Figure 103E.
(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.
(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.
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COMPONENT MAINTENANCE MANUAL Video Modulator Unit (VMU)(38)
