26
8. Troubleshooting Block
Troubleshooting Block
Aside from confirming the normal operating signals and voltage already discussed in this course, the digital
board can be troubleshot by dividing the board into specific sections using various normal operating modes.
Figure 8-1 and the text below will describe how this can be accomplished.
1/21/02
FIGURE 8-1 - TROUBLESHOOTING BLOCK
6A124
IC1401
DSP
5.1 CH.
AUDIO
INPUT
SIGNALS
IC1301
DIGITAL
AUDIO
DECODER
84
IC1403
BUFFER
IC1005
DIGITAL
INPUT
SELECT
IC1101
DIGITAL
I/F
RECEIVER
DIGITAL
INPUTS
IC1402
SRAM
85
DATA
DATA
DATA
ADDRESS
IC1503
CODEC
INPUT
CIRCUIT
AUDIO
INTERFACE
OUTPUT
CIRCUIT
9
DATA
DIGITAL INPUT
PATH ONLY
IC1504
IC1554
4R AMPS
2 CH.
AUDIO
INPUT
SIGNALS
IC1502
OUTPUT
SELECT
5.1 CH.
AUDIO
FROM J307
5.1 CH.
AUDIO
SIGNALS
TO AMPS
ANALOG INPUT
PATH ONLY
ANALOG INPUTS
FROM IC304
MAIN BOARD
Troubleshooting Procedure
As can be seen from Figure 8-1, the analog and digital inputs follow two separate paths up to IC1301, and then
the signal path is the same for both analog and digital all the way through to the speakers. This configuration can
be used to divide the circuit into sections and to determine in which IC a problem is occurring. The digital board
can be divided into five sections using various inputs and receiver self tests. The following steps are not in any
particular order and can be performed in any order to better conform to the specific problem at hand:
Procedures:
1) The
5.1 Channel Input
(J307) can be used to completely bypass the digital board circuitry. This input is
applied directly to IC1502. The circuits being tested are IC1502 and all audio and power amplifiers that
follow. A DVD player with a 5.1 Channel output would be used for this test.
2) The
2 Channel (2CH) Mode (**with an analog Input signal**)
can be selected to test IC304 (not shown
on Main Board), IC1502 and all audio and power amplifiers that follow. Once again, all digital board
circuitry is bypassed.
3) Set the receiver for
AFD or any Sound Field (e.g. Normal Surround)
, and select an
Analog Input
to set
up and test the following signal path:
Analog input
⇒
IC304
⇒
IC1504
⇒
IC1554
⇒
Partial IC1503
⇒
IC1301
⇒
IC1403
⇒
IC1404
⇒
Partial IC1503
⇒
IC1502
⇒
Audio Amps
****ICs bypassed are IC1005 and IC1101
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