SUBWOOFER OPERATION AUDIO SIGNALS CHECK

Check 5570TK

Hi-Fi system

Foreword.

In order to carry out this test correctly any music Compact Disc must be correctly inserted in the CD cartridge.

1. Amplifier input signals check

- Switch the radio on

- Go into Voltmeter mode and connect the Voltmeter probes to the amplified Subwoofer at pins C5 and B4

- Using the Examiner select a 20 Volt end of scale and 5 seconds, press the Start button and the values of the image that appear should be evaluated with a tolerance of around 20% and should be similar to the oscillogram shown below

- Connect to pins C6 and B6 and repeat the test

2. Amplifier output signals check

Repeat the test as in step 1, connecting the voltmeter probes first to pins A2 and A3 and then pins A4 and A5

Subwoofer connector

Amplifying the graphic trend of the voltage, the signal displayed should be similar to the following

- The presence of this graph, displayed at the subwoofer input, shows that the audio signals are arriving correctly.

- If the audio is missing from the subwoofer output, and the power supply and start-up enablement checks have not revealed faults,

the cause of the fault lies with the subwoofer amplifier, which should therefore be replaced

Whenever the audio signal at the amplifier input looks like the following;

Check the continuity/insulation of the wiring between the radio and subwoofer

Amplifier status positive recognition signal check

- Turn the key to the MAR position

- Connect between pin 3 of connector C of the amplifier and earth and check for the presence of an output voltage of around 12 Volts.

Subwoofer amplifier enablement signal check

- Turn the key to the MAR position

- Connect between pin 2 of connector C of the amplifier and earth and check for the presence of an input voltage of around 12 Volts

- If the wiring between the radio and subwoofer does not show any faults, and the audio signals are interrupted: replace the radio

- If the audio signals are present at the subwoofer input and interrupted at the output: replace the subwoofer amplifier - If the audio signals are present at the subwoofer output

- Check the continuity of the wiring between subwoofer output and loudspeakers. If OK replace loudspeakers