33
DISASSEMBLY PROCEDURES
6.4
Unplug the audio output wiring harness
from the power supply / amplifier PCB (8) at
CON301.
6.5
. Using a small Phillips-head screwdriver,
remove the one screw that secures the rear
panel (18) to the lower chassis housing (10).
Lift out the rear panel.
7. Front Panel Removal
7.1
Perform procedure 1.
7.2
Lift out the front panel (4).
Re-assembly Note:
Be sure to align the
front panel so that the Bose
®
logo is facing
the correct direction.
Required Equipment:
•
dB meter
•
Audio Signal Generator w/balanced output
•
Distortion meter
•
4 Ohm, 250 Watt load resistor
•
Digital Multimeter
•
4 Ohm full range speaker
•
1/4” TRS 600 Ohm test plug (see page 41)
•
1/4” TRS balanced input cable
•
1/4” TS unbalanced input cable
•
Amplifier output test cable (see page 41)
Test Setup Notes:
1.
Make measurements on the output using
an 80 kHz Low Pass Filter.
2.
Remove the input signal after tests with
high levels to avoid overheating the amplifier
and load.
3.
There are 120V and 220-240V versions of
this product. The voltage version is indicated
on the amplifier’s product label.
1. DC Offset Test
1.1
Connect the output of the A1 to the 4
Ohm load.
1.2
Power on the unit, with no input signal
present.
1.3
Measure the DC voltage across the load.
It should be less than +/- 30 mV.
2. Gain and Signal LED Balanced
Input Test
2.1
Connect the signal generator to either of
the A1 input jacks with a balanced, 1/4” TRS
cable.
2.2
Connect the output of the A1 to the 4
Ohm load.
2.3
Power on the unit
2.4
Apply a 1 kHz, -10 dBV (Tip to Ring)
signal to the input.
2.5
Reference a dB meter (80 kHz LPF) to
the input level. Measure the gain output at
the load. It should be +24.0 +4.0 dB.
3. Gain and Signal LED Unbalanced
Input Test
3.1
Connect the signal generator to either
of the A1 input jacks with an unbalanced,
1/4” Tip-Sleeve (TS) cable
Test Procedures
