Audiolab 8000S, Service Manual

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9
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
4.2.18.
4.2.19.
4.2.20.
4.2.21.
4.2.22.
4.2.23.
4.2.24.
4.2.25.
4.2.26.
Action
Measure offset
of protection
circuit
Disconnect DC
power supplies
Fix any faults
Connect
amplifier to AC
power input
Measure left
channel supply
rails
Measure right
channel supply
rails
Check
operation of
mute relay
Check
preamplifier
supply rails
Left channel
Check power
amplifier
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
V DC
Details
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.
Measure volatge across D713 (TP 1+ and
TP 1-) and D714 (TP 2+ and TP 2-) .
Volatge should be 44 V ± 2.5 V.
Measure volatge across D813 (TP 3+ and
TP 3-) and D814 (TP 4+ and TP 4-) .
Volatge should be 44 V ± 2.5 V.
Connect negative probe to 0 V (TP 0) .
Connect positive probe to cathode of D951
(TP 23) .
Switch on AC power button.
Voltage should increase slowly from 0 to
12 V then relay should operate and voltage
should increase to 41 V ±2 V.
Connect negative probe to 0 V (TP 0) .
Connect positive probe to 30 V test point
(TP 19) . Voltage should be 28 V ±3 V.
Connect positive probe to 10 V test point
(TP 15) .
Voltage should be 10 V ±0.5 V.
Connect positive probe to 5 V test point
(TP 16) .
Voltage should be 5 V ±0.3 V.
Measure voltage across R731
(TP 5+ and TP 5-) .
Voltage should be 0.85 V ±0.1 V.
Measure voltage across R735
(TP 6+ and TP 6-) .
Voltage should be 0.85 V ±0.1 V.