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Chapter 14, Diagnostics Descriptions
Description Of Audio Diagnostics (AFDIAGS3)
N:\mkt\MANUALS\HP8924C\ALR\diagnos.fb
Audio Analyzer 2 Paths
This test checks Audio Analyzer 2 (A36). The source for this test is Audio
Frequency Generator 1 which is always set to AC. The signal from Audio
Frequency Generator 1 passes through the Modulation Distribution assembly,
through the Modulation Select Source Switch, and the Monitor Select
Multiplexer. It bypasses Audio Analyzer 1. The test paths are illustrated in
The gain of the Detector Range Amplifier (Paths 5 to 7) is 3.16, 10, and 31.6
corresponding to gains of 10 dB, 20 dB, and 30 dB. The gain of the Post-Notch
Ampl
L
figure 68, "Audio Analyzer 2 Path 8," on page 579
) is
similar.
The variable-frequency Notch Filter is tested at the beginning of this test. The
input is set to 1 kHz and the notch output is nulled using a notch-error detector in
conjunction with a DAC-setting routine. The notch-error detector is not shown in
figure 68, "Audio Analyzer 2 Path 8," on page 579
, but it is multiplexed with the
pre-notch RMS detector
.
The test then proceeds as if the filter were fixed at 1 kHz and measurements are
made at the output of the filter for input frequencies of 500, 1000, and 2000 Hz.
The failure codes for Audio Analyzer 2’s paths are as follows:
Table 121
Audio Analyzer 2 Paths Failure Codes
Failure Codes
Probable Cause(s)
Code 1
Suspect Audio Analyzer 2 assembly (high) (Peak Detector Select Switch stays
in position b.)
Code 2
Suspect Audio Analyzer 2 assembly (high) (Neg Peak Detector faulty or
DVM Select Switch stays in position b.)
Code 3
Suspect Audio Analyzer 2 assembly (high) (Coupling capacitor following
Peak Detector Buffer Amplifier faulty, not shown in figure.)
Code 8
Suspect Audio Analyzer 2 assembly (high) (De-Emphasis LPF faulty or De-
Emphasis select switch stays in position a.)
Code 112
Suspect Audio Analyzer 2 assembly (high) (Detector Range Amplifier stays at
gain=1.)
Code 120
Suspect Audio Analyzer 2 assembly (high) (Peak Detector Select Switch stays
in position a.)
Summary of Contents for 8924E
Page 52: ...Contents 52 N mkt MANUALS HP8924C ALR 8924CE TOC A Error Messages ...
Page 53: ...Contents 53 N mkt MANUALS HP8924C ALR 8924CE TOC Index 633 ...
Page 54: ...Contents 54 N mkt MANUALS HP8924C ALR 8924CE TOC ...
Page 137: ...137 N mkt MANUALS HP8924C ALR per_adj fb 4 Periodic Adjustments ...
Page 449: ...449 N mkt MANUALS HP8924C ALR service fb 10 Service Screen ...
Page 455: ...455 N mkt MANUALS HP8924C ALR blkdia fb 11 Block Diagrams ...
Page 522: ...522 Chapter 11 Block Diagrams Assembly Details N mkt MANUALS HP8924C ALR blkdia fb ...
Page 613: ...613 N mkt MANUALS HP8924C ALR errmssg fb A Error Messages ...