Wharfedale SW150 Active Subwoofer help - diyAudio
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Old 23rd May 2015, 11:12 PM   #1
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Default Wharfedale SW150 Active Subwoofer help

Morning All,

The units red LED lights up, but no sound at all.
I have tested all components, except for the relays, the zener diodes, and the ICs' (I do have a list of measurements but don't understand them). If a component did not test correctly in circuit, I have removed, tested, and refitted, and so far all test O.K..
The unit was not fitted with the Green Auto-LED (there is no mount / hole), which I have subsequently fitted (the PCB has the required header). This had no effect and does not light.
I get +15v & -15v at Con105 shown centre of the schematic which connects both PCBs'.
I get +44.8v on the collectors of Q107/8 & -44.8 at Q110/111 output transistors (?).
I have a reasonable DMM, but no 'scope.

Cheers & hope someone can help,

Attached Images
File Type: png SW150 Schematic.png (140.4 KB, 52 views)
Attached Files
File Type: pdf wharfedale_pc12_dx_sm.pdf (389.4 KB, 22 views)

Last edited by hybridtech; 23rd May 2015 at 11:16 PM. Reason: Added Service Manual. Original Schematic too small
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Old 23rd May 2015, 11:54 PM   #2
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Have you got 0V DC on the emitters of the output transistors?
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Old 24th May 2015, 01:08 AM   #3
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Originally Posted by JonSnell Electronic View Post
Have you got 0V DC on the emitters of the output transistors?
The 4 main Q107/8 & Q110/111 show 63mV to 66mV all in the +ve range, no -ve.
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