PARKnSHOP-AV-933A silent amplifier power on the main speakers, surround, reset to normal |
| Time£º2015-05-26 08:11:43 Source£ºNetwork Author£ºUnknown Clicks£º1617 |
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kyEservice manual download site
kyEservice manual download site
Suddenly blow good mood suddenly gone. Calm down, first thought is just switched transistor on poor quality, but the weld measured is not damaged and replaced a well fitted, try "failure" remains the same, it seems that this is not the problem.kyEservice manual download site
kyEservice manual download site
Tone control circuits are "failures" led to the l-channel not working properly? To validate the judgment, retrace the tone control switch test machine, and l-channel noise disappears, sound back to normal. For further confirmation, turn down the volume (to prevent the left speaker is damaged by impact to), then press the tone control switch, relay and immediately "pop" sound, contacts arcing again, indicating "failed" certainly the tone control circuit. See photos of the tone control for the relevant circuit (only drawing l-channel). In Figure 1, 'VR1 volume potentiometer, VIL3 adjust the potentiometer for bass, VK4 treble adjustment potentiometer, they were single in 6-foot structure, control of both channels. After VR1, l-channel signal to enter the integrated operational amplifier ICl (NE5532) buffer, amplified audio signals via K2 tone control switch for selecting the output. When K2 in the diagram position (upper). IC! zoom Hou of audio signal was directly rushed to subordinate poor moving zoom circuit, then main channel voice normal; Dang K2 placed lower Shi, ICl output of audio signal first entered to shipped put IC2 for core of tones processing circuit (figure in the dashed box by shows), by level tones after from shipped put IC2 anti-phase end ¢Þ feet entered, processing Hou of signal from sadly feet output, after K2 rushed to subordinate zoom device.kyEservice manual download site
kyEservice manual download site
Press tone control when switch to prevent the speaker from an instant-hit damage, overhaul, switching at K2 to tone control (slave), the relay instantly jumped off, 2 seconds after the snap and then connected to the speakers. As mentioned above, the noise emitted strong at this point only the l channel r channel sound normal. Focusing on the tone control circuits are checked, check around the IC2 components are not damaged, measuring amplifiers ¢ß pin voltage of 12V normal voltage is 0V, this serious abnormal voltages to give them lower differential amplifiers led to the potential serious deviation from the normal range, so that the output relays have instant protection. Suspected IC2 is damaged, replacement after commissioning, "glitch" still. VR3, VK4 damage result in improper input caused the "fault"? VR3, VK4, installed in the Control Panel, remove more trouble, according to past experience, generally does not break easily. But patiently to remove the VR3 with a multi-meter, VR3 set of pins in open circuit, this group is used to adjust the l. After the replacement, "failed" completely ruled out.
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