Test Set-Up Parameters And Equipment; Bass Box Only Troubleshooting Procedures - Bose Loewe Concertos Acoustimass 61247 Service Manual

Test Set-up Parameters and Equipment

Use the disassembly/assembly procedures found in the AM25/30P Series II service manual part
number 230-90374.921, to access the PCBs.
Speaker Output Loading:
Unless testing the amplifier for its rated power output, all tests are to be performed with the
speaker outputs unloaded. The amplifier can be tested with loads as long as the PCB is still
mounted in its heatsink.
Left Front Output:
Right Front Output:
Center Output:
Left Surround Output:
Right Surround Output:
Bass Channel Output:
Equipment Requirements:
Test Cable part number 169-90377.906
Test Set-up
1. Set up the bass box as shown in the Test Setup Diagram, (Figure 45. in the Appendix)
Note: Since you have only the bass box for troubleshooting and are not using a PC to
communicate with the module, you will not use the connectors for the PC, the audio jacks or the
digital input jack on the test cable. You will use the 3.5mm mono jack and the 9 Volt battery to turn
the module on.
When the module is powered on using the battery or a DC power supply, it will come up with
the amplifiers muted. You will not be unmuting the amplifiers and passing an audio signal while
performing the tests in this section.
If the module passes the tests in this section, you can use the amplifier test procedures to test the
amplifier board on its own and verify that it is okay.

Bass Box Only Troubleshooting Procedures

1. Module Power-up
1.1 With the top cover removed and the line cord connected to an AC mains source, connect the 9
Volt battery to the 3.5 mm mono plug, TIP (+) RING (-), located on the test cable. This will power
up the module.
Note: If you disconnect AC mains from the module, you will need to disconnect and reconnect
the 9 Volt battery to the 3.5 mm plug to get the module to power up again.
2. Check for Voltage at the Transformer
2.1 Check for voltage at the transformer secondary. If there is voltage at the transformer
secondary, skip to procedure 4. If there is no voltage on the transformer secondary, continue on
to step 2.2.
8 Ohm, 1%, 50W
8 Ohm, 1%, 50W
8 Ohm, 1%, 50W
8 Ohm, 1%, 50W
8 Ohm, 1%, 50W
4 Ohm, 1%, 100W
5