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JBL LSR4312sp Broken!!!
Old 26th July 2014
  #1
JBL LSR4312sp Broken!!!

Horrible news, My JBL LSR4312sp subwoofer broke today...

I think the amp fried.

Today was a hot day.

I was mixing for hours as usual. Had it turned up working on a bass heavy mix. All of a sudden i hear a horrible noise sounded like a combination of a speaker blowing out and and farting at the same time. After this the subwoofer stopped outputting sound. Turned everything off and left the room... Now its been an hour and I turned it on to see if it works... nope... I smell some type of electronic burn so I know something burned out. Woofer is not blown tho. Its still fine.

I'm Broke at the moment and this is not a cheap subwoofer... But its very dear to me... and I need it back working to finish this project I'm mixing...

Any idea whats wrong with it and how much it is to fix something like this?

Thanks GS
Old 26th July 2014
  #2
Gear Head
 
futura2012's Avatar
 

In many cases on amp boards its the Reservoir Caps that go but without seeing a pic of the board im kind of stabbing in the dark. You could also look at the Bridge Rectifier they commonly fry also.

Are you the type that likes to pull things apart and experiment or does the thought of this fill you with horror?

You would be amazed at what you can do with a $5 multimeter, solder sucker, solder, and soldering iron.


First of all establish if the actual driver is dead or the amp has gone.

Using multimeter switch it to diode check. then touch the two leads across the + and - terminal you should hear a small click.

Secondly set the multimeter to resistance and measure across the + and - you should see between 4-8 ohms resistance.

if no resistance then switch the multimeter to bleep. connect this across the terminals. if no bleep driver dead. if bleeps you are probably okay.


When conducting these tests it is vital you get a good contact. possibley use a nail file or needle file to file the contacts slightly. Otherwise you will get false readings and assume the speaker is fried when infact its okay.

from your description it sounds like a frazzled amp but always best narrow down first before assuming anything. Otherwise you waste a lot of time
Old 26th July 2014
  #3
Gear Head
 
futura2012's Avatar
 

if you can get access to another one of these things working life becomes a lot lot easier
Old 26th July 2014
  #4
Quote:
Originally Posted by futura2012 View Post
In many cases on amp boards its the Reservoir Caps that go but without seeing a pic of the board im kind of stabbing in the dark. You could also look at the Bridge Rectifier they commonly fry also.

Are you the type that likes to pull things apart and experiment or does the thought of this fill you with horror?

You would be amazed at what you can do with a $5 multimeter, solder sucker, solder, and soldering iron.


First of all establish if the actual driver is dead or the amp has gone.

Using multimeter switch it to diode check. then touch the two leads across the + and - terminal you should hear a small click.

Secondly set the multimeter to resistance and measure across the + and - you should see between 4-8 ohms resistance.

if no resistance then switch the multimeter to bleep. connect this across the terminals. if no bleep driver dead. if bleeps you are probably okay.


When conducting these tests it is vital you get a good contact. possibley use a nail file or needle file to file the contacts slightly. Otherwise you will get false readings and assume the speaker is fried when infact its okay.

from your description it sounds like a frazzled amp but always best narrow down first before assuming anything. Otherwise you waste a lot of time
hey thanks for the reply! I would like to do that test can you tell me exactly where I should measure? Do i need to open up the subwoofer or what exactly?

Unfortunately I'm not too tech savvy ... about 6 months ago, i had a microphone problem where the diaphragm had come loose and fell into the head of the mic... I opened it up to put it back and accidentally broke the mic completely... (i'm heavy handed)... ended up getting it fixed after that and paid about 300 for a new diaphragm

I might be able to fix it myself... but if I open up this sub (Its Huge weighs like 40 pounds), I don't want to damage it in any way... Let me know what you need from me and I can provide it... if not I'll call some shops on monday and see what they charge (I know it wont be cheap )

Quote:
Originally Posted by futura2012 View Post
if you can get access to another one of these things working life becomes a lot lot easier
i wish i knew someone else with this sub
Old 27th July 2014
  #5
Quote:
Originally Posted by futura2012 View Post
In many cases on amp boards its the Reservoir Caps that go but without seeing a pic of the board im kind of stabbing in the dark. You could also look at the Bridge Rectifier they commonly fry also.

Are you the type that likes to pull things apart and experiment or does the thought of this fill you with horror?

You would be amazed at what you can do with a $5 multimeter, solder sucker, solder, and soldering iron.


First of all establish if the actual driver is dead or the amp has gone.

Using multimeter switch it to diode check. then touch the two leads across the + and - terminal you should hear a small click.

Secondly set the multimeter to resistance and measure across the + and - you should see between 4-8 ohms resistance.

if no resistance then switch the multimeter to bleep. connect this across the terminals. if no bleep driver dead. if bleeps you are probably okay.


When conducting these tests it is vital you get a good contact. possibley use a nail file or needle file to file the contacts slightly. Otherwise you will get false readings and assume the speaker is fried when infact its okay.

from your description it sounds like a frazzled amp but always best narrow down first before assuming anything. Otherwise you waste a lot of time
Hey man i took this into an authorized jbl repair center and the guy cant seem to get the sub open to work on it... any ideas how?
Old 1st November 2014
  #6
Quote:
Originally Posted by kangking View Post
Hey man i took this into an authorized jbl repair center and the guy cant seem to get the sub open to work on it... any ideas how?
thread update. sub was repaired. was a blown voice coil in sub. so i guess sub was blown. although it didn't seem blown. it was. sub was replaced. and actually sounds better than ever
Old 16th December 2015
  #7
Gear Addict
Quote:
Originally Posted by kangking View Post
thread update. sub was repaired. was a blown voice coil in sub. so i guess sub was blown. although it didn't seem blown. it was. sub was replaced. and actually sounds better than ever
What was the cost?
Old 16th December 2015
  #8
Quote:
Originally Posted by deejay2x View Post
What was the cost?
About 300. Wasnt too bad actually, it all worked out for the best. Sub working better than ever now! Plus i learned a lot about bass management and how to mix something bass heavy and still protect your subwoofers and amps. A high pass filter at 30hz is the way to go. That way you can get the song competitively loud, with tons of sub, but without the risk of blowing a speaker or amp. It was a good $300 lesson honestly
Old 4 weeks ago
  #9
Gear Nut
 

Quote:
Originally Posted by kangking View Post
About 300. Wasnt too bad actually, it all worked out for the best. Sub working better than ever now! Plus i learned a lot about bass management and how to mix something bass heavy and still protect your subwoofers and amps. A high pass filter at 30hz is the way to go. That way you can get the song competitively loud, with tons of sub, but without the risk of blowing a speaker or amp. It was a good $300 lesson honestly
Do you still have this sub? If so, still working for you?



Mine shut off and won't come back on. Took it apart last time and it work again -about a year ago.

Never abused in during my ownership but stuff happens.
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