Audiolab 8000S, Руководство по обслуживанию

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10
4.0 f u n c t i o n a l t e s t s
4.2 Functional test procedure
For test point (TP) references, see section 6.0 Test Points.
No
4.2.27.
4.2.28.
4.2.29.
4.2.30.
4.2.31.
4.2.32.
4.2.33.
4.2.34.
4.2.35.
4.2.36.
4.2.37.
Action
Left channel
Measure
amplifier offset
Left channel
Measure
preamplifier
Right channel
Check power
amplifier
Right channel
Measure
amplifier offset
Right channel
Measure
preamplifier
Measure offset
of protection
circuit
Fix any faults
Allow amplifier
to warm up
Left channel
Check bias
Right channel
Check bias
Readjust bias
Test Equipment
Multimeter set to
mV DC
Multimeter set to
V DC
Multimeter set to
V DC
Multimeter set to
V DC
Multimeter set to
V DC
Multimeter set to
mV DC
Multimeter set to
V DC
Multimeter set to
V DC
Details
Connect negative probe to 0 V (TP 0) .
Connect positive probe to R749 (TP 9) .
Voltage should be <5 mV.
Connect positive probe to R518 (TP 12) .
Voltage should be 14 V ±1 V.
Measure voltage across R831 (TP 7+ and
TP 7-)
Voltage should be 0.85 V ±0.1 V.
Measure voltage across R835
(TP 8+ and
TP 8-)
Voltage should be 0.85 V ±0.1 V.
Connect negative probe to 0 V (TP 0) .
Connect positive probe to R849 (TP 10) .
Voltage should be <5 mV.
Connect positive probe to R618 (TP 13) .
Voltage should be 14 V ±1 V.
Connect positive probe to cathode of D943
(TP 11) .
Voltage should be <5 mV.
If any faults have been detected, repair and
return to the beginning of this test
procedure .
Leave on for 20 minutes with cover on. It is
not necessary to screw cover down.
Connect probes across legs of R748
(TP 1- and TP 2-) .
Voltage should be 22 mV ±0.5 mV.
If necessary, adjust RV701
(TP 24) .
Connect multimeter probes across legs of
R848
(TP 3- and TP 4-) .
Voltage should be 22 mV ±0.5 mV.
If necessary, adjust RV801
(TP 25) .
Leave on for a further 10 minutes.
Repeat 4.2.35 and 4.2.36.