Bose 2150 - Page 54

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TEST PROCEDURES
12.4 Use a 0.1 Ohm, 2 Watt (or greater)
resistor to short across the left amplifier
channel's 4 Ohm load resistor. Verify that
the amplifier output mutes, the amplifer
resets and attempts to turn on after a short
delay but continues to cycle as long as the
short is in place.
12.5 Remove the short across the left
amplifier channel load resistor and verify
that the amplifier turns on.
12.6 Repeat steps 12.3 to 12.5 for the right
channel.
13. DC Offset Test
13.1 On the front panel of the amplifier, set
the gain controls fully CW. On the rear panel,
set the configuration dip switches (7) OFF
(down).
13.2 Connect a 4 Ohm load resistor to
the left and right channel 4 Ohm speaker
outputs.
13.3 With no input signal applied, measure
the DC voltage at the amplifier left and right
channel 4 Ohm output terminals. It should
be < 15 mVdc.
14. Power Sequencing Test
14.1 On the front panel of the amplifier, set
the gain controls fully CW. On the rear panel,
set the configuration dip switches (7) OFF
(down).
14.2 Connect a 4 Ohm load resistor to
the left and right channel 4 Ohm speaker
outputs.
14.3 On the amplifier front panel, set the
power switch to STANDBY. Verify that the
amber standby LED lights.
14.4 Apply +10 Vdc to the sequence connec-
tor RECV and GND terminals (from left to
right, the terminal pin connections are GND,
SEND and RCV).
14.5 Verify that the amplifier powers up
normally.
14.6 Use a DC voltmeter to measure the
voltage at the sequence connector SEND
and GND terminals. It should be 14.4 Vdc +
1.5 V.
15. Thermal Shutdown Test
15.1 Disconnect the amplifier from AC mains
power. Remove the amplifier top cover using
disassembly/assembly procedure 1.
15.2 Locate the violet wire running from the
power transformer to the rectifier PCB
assembly. Unplug the wire from terminal
WL402.
CAUTION: Components with dangerous
voltages are exposed when operating the
amplifier with the top cover removed.
15.3 Reconnect the amplifier to AC mains
power. Turn the amplifier power switch ON.
Confirm that both THERMAL LEDs light and
that the PROTECT LEDs cycle ON then
OFF. The READY LEDs should not light.
15.4 Turn the amplifier power switch OFF.
Disconnect the amplifier from AC mains
power. Reconnect the violet power trans-
former lead to WL402 on the rectifier PCB
assembly.
15.5 Reconnect the amplifier to AC mains
power. Turn the amplifier power switch ON.
Confirm that both PROTECT LEDs light,
then cycle OFF with both READY LEDs
lighting after a short delay.
15.6 Disconnect the amplifier from AC mains
power. Install the amplifier top cover using
disassembly/assembly procedure 2.