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Post by Michael on Sept 4, 2013 13:47:49 GMT -5
I have a JBL PB-12 subwoofer that made a loud boom and after that it does not respond to the signals from the receiver. Occasionally, it makes a series of rapid ticking sound( sounds like a toy machine gun sound). Need help to diagnose the problem. Thank you!
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Post by mastertech on Sept 4, 2013 14:34:56 GMT -5
Give me a couple hours and I'll respond to this.
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Post by mastertech on Sept 5, 2013 20:00:50 GMT -5
I need any info off the label on the back of the unit. Then pull the amp bard out and give me any numbers on the board such as version and/or part numbers.
When you turn it on does any leds light up? Check with and without an input signal.
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Post by Michael on Sept 6, 2013 17:04:48 GMT -5
I emailed you couple of pictures from the board. Green LED does not come on at all. Red LED light(standby)comes on with or without an input signal.  [/a]   |
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Post by mastertech on Sept 7, 2013 10:31:31 GMT -5
I cannot see the serial number in those pics. What is the number?
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Post by Michael on Sept 7, 2013 11:33:43 GMT -5
Serial #: PB12 AM0035-023630
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Post by mastertech on Sept 9, 2013 14:10:53 GMT -5
You need to test for these voltages. Speaker must be connected when making any tests. Not sure if an input signal is required but lets start here. Just be careful not to get shocked. DMM on DC voltage.  |
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Post by Michael on Sept 10, 2013 10:26:36 GMT -5
I get all the voltages correctly with exception of ;
1= -86.1 V
15= -85.8 V
FYI;
2,3,4,16,17,18= 92.5 V
6,7,8,20,21,22= -92.5 V.
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Post by mastertech on Sept 10, 2013 14:13:57 GMT -5
Diode test D5 and D6.
Resistance test R6, 47 ohms.
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Post by Michael on Sept 10, 2013 15:24:19 GMT -5
D5= 0.660 V
D6= 0.655 V
R6= 46.4 Ohms
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Post by mastertech on Sept 10, 2013 15:49:37 GMT -5
You probably have a bad amp assembly which is that black box sticking up off the board. It is sealed and is suppose to be changed as the whole box. I have never had one to try cutting it open so I don't know if the insides are accessible. Not sure if the module is available from any suppliers. The part number is 60302. Your sub is a revision 1. If it was a revision 2 then the amp section is not enclosed and is repairable.
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Post by Michael on Sept 10, 2013 16:06:25 GMT -5
Thanks... we tried!!
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