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Post by 24century on Nov 10, 2017 1:22:14 GMT -5
Had a JBL Venue Sub12, it is working great while it works before but not anymore
It start that noise and freq getting slower then it will disappear after a mins, when I finally in working stage the bass is not powerful, start reacting worse when the weather cools down in the recent days, believe it is power related problem, have the service book ready, need help!!
Background: it happened about 2-3 years ago, open it up and found the fry around power sectioninside, see photos attached.
did some repair and replaced capacitors also one set of the big one and few resistors, appeared problem solved back then, but it happened again and it is more serious this time with that noise during startup, led lights is in good status of indications.
appear to me that it may related with hi-res music source, any suggestion or comment? |
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Post by 24century on Nov 10, 2017 15:09:06 GMT -5
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Post by mastertech on Nov 11, 2017 10:52:35 GMT -5
Have you verified it is not the source causing the noise/problem?
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Post by 24century on Nov 11, 2017 12:19:16 GMT -5
Have you verified it is not the source causing the noise/problem? Did that by running speaker channel test but will double verify that this afternoon, including RCA both channel input test
Will have to do a speaker extension so I can perform test with PCB board out of enclosure
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Post by 24century on Nov 11, 2017 17:55:13 GMT -5
Finally took the time and space to do the test, it is not the source problem verified now.
When power up from cold with signal, power light from red blinks with green, bass speaker start to make that gripping noise, the sound has some noise inside (woofer only without additional speaker attached), not much of the solid bass being produced
When music source stopped, the green light start to blink with red light, freq from fast to slow with gripping noise output to speaker eventually it puts woofer into idle mode and light went red, tested with both LFE and Normal mode.
after 20 mins plus of playing, the woofer starts to get to normal working stage as it suppose to be and it went to idle after 5 mins of inactive, light turns red
Did checked all soldering points to make sure prior to the 1st turn on
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Post by mastertech on Nov 11, 2017 18:21:09 GMT -5
Ok. So it is not the source. Did you try a different speaker?
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Post by 24century on Nov 11, 2017 22:40:53 GMT -5
Not the source for sure, hooked up an different woofer to the same receiver and it works right away, Although i do prefer this 12” JBL a lot
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Post by mastertech on Nov 11, 2017 22:57:30 GMT -5
I think you misunderstood my last question. I meant, try a different speaker in your JBL. This is to rule out that the problem with the JBL is the speaker itself.
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Post by 24century on Nov 11, 2017 23:41:04 GMT -5
I think you misunderstood my last question. I meant, try a different speaker in your JBL. This is to rule out that the problem with the JBL is the speaker itself. Figured that’s what u mean just now, then return to my iPad to write. So far don’t have a 12” or similar speaker for that test, will figure out a substitution speaker to test tomorrow. That wouldn’t explain the blinking indicator light color since the speaker impendence won’t change. But will try that tomorrow morning with a smaller speaker under low volume and let u know |
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Post by 24century on Nov 12, 2017 14:13:30 GMT -5
Did the test with a different speaker attached, it is not the speaker either.
During the cold start for the 1st 20-30 mins, there are some strange higher freq sound was being produced inside, don't know where that comes from and it is hard to describe
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Post by 24century on Nov 12, 2017 14:47:44 GMT -5
only JBL has the PCB with transformer available (Part Number: 010-0N20-05346-E) plus tax and shipping, not worth it
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Post by mastertech on Nov 12, 2017 16:21:55 GMT -5
Is there any DC voltage on the speaker out terminals?
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Post by 24century on Nov 12, 2017 16:29:25 GMT -5
Is there any DC voltage on the speaker out terminals? Yes, there is, will get the voltage # as needed |
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Post by 24century on Nov 12, 2017 18:14:53 GMT -5
Is there any DC voltage on the speaker out terminals? There is but very low DC output as 0.01v while in working stage, speaker connected and can hear sound out. That is getting hard to even get start, focused on bigger capacitors they all visually looks good but did find one cap C78 is not listed on the service Book, see foto  |
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Post by mastertech on Nov 12, 2017 19:02:46 GMT -5
Get me the DC voltage readings across the following caps:
C6____
C8____
C4____
C9____
C53____
C50____
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