Question about JBL Venue SUB12 Subwoofer
I have posted problem with humming noise on my JBL Venue sub 12. Every time I turn it on makes a terrible humming noise then turns off after about 15 seconds. Wanted to add this problem occurs even without cables hooked up. (so I dont think its a bad connection). Thanks.
I'm fairly sure this is a power supply problem; less likely, a shorted power output stage which may be a largish integrated circuit; this last one would probably be costly to replace.
A failed diode or filter capacitor in the supply can cause this by either (the diode) allowing unrectified AC to pass or (the capacitor) poor DC filtering of the rectified AC. Neither of these parts is expensive.
Diodes can be in a variety of different packages so giving guidance on these is tough. Capacitors of the type likely used as the main filters in your power supply will be cylindrical objects between 1/2" (12-13mm) to 1 1/2" (~37mm) in diameter and between 1/2" to 3" (~75mm) tall. Caps are in aluminum cases with shrink wrap that will have values given in microfarads (µF) and VDC (Volts DC). Often, when they fail, the exposed tops will bulge visibly as a sign of their failure and sometimes they will leak from the bottom rubber seal and there will be traces of a white deposit on the board around them. If you see such signs, replace them.
Checking power supply diodes could be done with any multimeter but unless the electrolytic capacitor(s) fails catastrophically as above, the main filter caps would need to be verified for value and losses with a capacitance meter which is too expensive to buy for home use. A plain-jane digital multimeter can cost <$20 US and would be useful for many other tests around your home and car as well.
Posted on Sep 06, 2008
Tips for a great answer:
Sep 13, 2011 | JBL Venue SUB10 Subwoofer
Sep 06, 2011 | JBL Venue SUB10 Subwoofer
Aug 18, 2011 | JBL Venue SUB10 Subwoofer
Jan 13, 2010 | JBL Venue SUB10 Subwoofer
Dec 15, 2009 | JBL Venue SUB10 Subwoofer
Nov 22, 2009 | JBL Venue SUB10 Subwoofer
Jul 13, 2009 | JBL Venue SUB12 Subwoofer
Dec 06, 2007 | JBL PB12 Subwoofer
Sep 10, 2007 | JBL PSW-D112 Speaker
731 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: