Bose AM-30P Manual de servicio - Página 29

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TEST SET-UP PARAMETERS

Before performing the tests described in these procedures, use the following test setup

parameters.

SPEAKER OUTPUT LOADING

All tests are to be performed with speaker outputs unloaded except for those specified in the

Amplifier Test. Outputs should be loaded as listed below.

Potentiometers R50 (treble control) and R306 (bass control) should be set to the center

position.

Apply AC mains voltage. Wait 100ms and apply +10VDC between J5 Pin 1 and 7, or (if

connected) power CD-20 on. Pin 7 is the ground reference point which has to be connected.

The microcontroller can be manually configured to operate in several different "Test Modes" to

facilitate input/output troubleshooting and repair without the need for a CD-20 music center (to

provide serial data commands to the microcontroller). This is necessary because, by default, all

volume control ICs (U8, U9, U12) are at minimum volume and all power amplifier stages are

muted in the absence of serial data input. The test modes are induced by grounding Pins 25, 26

and 27 (*labeled TEST 3, TEST 2 and TEST 1 on the top side of the PC board) of U601 as

follows:

Note: Ground out the test mode pins before powering up the AM-30P unit.

Test Modes

NOTE: To access this section of the PC board the top cover must be removed.