# repairing a jl audio 300/4



## shutmdown (Aug 24, 2008)

so i have distortion in my front right channel on my jl audio 300/4. has anyone else had this issue and how do i go about in fixing this issue? i have a soldering iron so if someone can direct me to look at a specific cap or resistor I can attempt to repair it myself. none of the internals look burnt. i did not find any loose solder points. thanks ahead of time


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## schmiddr2 (Aug 10, 2009)

Probably similar to this issue I had: http://www.diymobileaudio.com/forum...re-out-whats-wrong-my-amp-video-included.html


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## shutmdown (Aug 24, 2008)

schmiddr2 said:


> Probably similar to this issue I had: http://www.diymobileaudio.com/forum...re-out-whats-wrong-my-amp-video-included.html


exactly the same issue. so were you able to fix it by testing and replacing the bad transistors?


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## schmiddr2 (Aug 10, 2009)

No. I checked them all and didn't find any bad. So now I just have a disassembled amp. 

Chad just said it would be nice if it was a transistor leg busted, but it seems he was suggesting this,



chad said:


> Hint, transistors don't GENERALLY blow open, they CAN, but not generally. Resistors will however


I also checked resistors, but didn't see any out of tolerance.


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## DJ Welfare (May 18, 2011)

If you f*ck up your 300/4 I have a back up one to sell you just in case.


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## trojan fan (Nov 4, 2007)

Send it in to JL and call it a day....they will give you a new updated board(s)


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## Ampman (Sep 7, 2011)

If you haven't already gotten it fixed here's something to try. Take a reading of the voltages on one of the channels that are working properly from pre-amp through output stage. Make a note of your readings then compare those readings to the channel that's not working as it should any variations in voltage to that particular stage will give you an idea as to where to look for a problem and try signal tracing from one stage to the other that will cut down on the guess work as to where the problem really is hope that helps


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## shutmdown (Aug 24, 2008)

DJ Welfare said:


> If you f*ck up your 300/4 I have a back up one to sell you just in case.


how much? ive been looking at craigslist in case i do f#ck this one up


trojan fan said:


> Send it in to JL and call it a day....they will give you a new updated board(s)


can't its missing the serials and to reserialize it and repair it with shipping I could pick one up from craigslist...


Ampman said:


> If you haven't already gotten it fixed here's something to try. Take a reading of the voltages on one of the channels that are working properly from pre-amp through output stage. Make a note of your readings then compare those readings to the channel that's not working as it should any variations in voltage to that particular stage will give you an idea as to where to look for a problem and try signal tracing from one stage to the other that will cut down on the guess work as to where the problem really is hope that helps


im a noob can you tell me exactly where to take these measurements from?


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## daveds50 (Jun 10, 2011)

shutmdown said:


> how much? ive been looking at craigslist in case i do f#ck this one up


 if this happens, i'll buy the broken one. that goes to schmiddr2 too.


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## DJ Welfare (May 18, 2011)

I'd like $200 for it. I think that's a fair market value for it, mine is v2 and 10/10 functionally and 8/10 for appearance. If you're in the Los Angeles area we could meet up.


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## adrenalinejunkie (Oct 17, 2010)

If I remember correctly $180 will get you a repaired amplifier from JL. Sometimes, it's better to do that rather then investing on a used one from craiglist unless you fully test the amplifier.


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## trojan fan (Nov 4, 2007)

adrenalinejunkie said:


> If I remember correctly $180 will get you a repaired amplifier from JL. Sometimes, it's better to do that rather then investing on a used one from craiglist unless you fully test the amplifier.


Bingo, you are exactly right:beerchug:


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## shutmdown (Aug 24, 2008)

trojan fan said:


> Bingo, you are exactly right:beerchug:


yes only if the serials are intact and your the original owner. in my case, because the serials are missing theres a fee to have it re serialed.


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## aV8ter (Sep 4, 2009)

My 500/5 lost output on one of the 25x2 channels. Had the local JL dealer send it to JL to get repaired. I am picking it up tomorrow. Was $180 plus the cost to ship it there so about $200 all said and done for a completely gone through amp. Turn around time was about 2 months though. Kind of long but I wasn't using it currently.


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## DJ Welfare (May 18, 2011)

$180 + shipping + down time = inconvenient along with the strict terms of condition

Didn't know JL is strict on serial # and being original owner = ftl


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## aV8ter (Sep 4, 2009)

DJ Welfare said:


> $180 + shipping + down time = inconvenient along with the strict terms of condition
> 
> Didn't know JL is strict on serial # and being original owner = ftl


I am at least the 4th owner of this particular amp(bought it from at least the 1st owner and passed it on to two of my friends before it came back to me). Got scammed(my fault though) originally when i purchased it of Craigslist. Was listed as "NIB" and it was not. Was dark out and I didn't look it over too hard. Realized it the next day and the seller never picked up his phone thereafter to resolve the issue. Shame on me.

Is has a serial number but I did not have to produce any proof of purchase to have it repaired.


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## daveds50 (Jun 10, 2011)

good god you guys pay too much to get amps repaired... JL's are easy fixes. 

anyway, would still like to buy the broken amp.


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## aV8ter (Sep 4, 2009)

daveds50 said:


> good god you guys pay too much to get amps repaired... JL's are easy fixes.
> 
> anyway, would still like to buy the broken amp.


I don't mind paying for peace of mind. It is more honestly getting refurbished for that price, not receiving a quick fix.


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## trojan fan (Nov 4, 2007)

aV8ter said:


> I don't mind paying for peace of mind. It is more honestly getting refurbished for that price, not receiving a quick fix.


Exactly!!!!


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## daveds50 (Jun 10, 2011)

aV8ter said:


> I don't mind paying for peace of mind. It is more honestly getting refurbished for that price, not receiving a quick fix.


 anyone who repairs correctly, does the exact same thing as they do. i have no idea why you think you are getting more for your money by paying that much. i know _exactly_ what they do.


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## adrenalinejunkie (Oct 17, 2010)

daveds50 said:


> anyone who repairs correctly, does the exact same thing as they do. i have no idea why you think you are getting more for your money by paying that much. i know _exactly_ what they do.



Possibly you can repair the OP's amplifier?


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## daveds50 (Jun 10, 2011)

adrenalinejunkie said:


> Possibly you can repair the OP's amplifier?


 i could, but i'd rather buy it.  

im high volume, and quite busy. when i buy broken electronics, i dont have to time slot it in my schedule. i just repair it when i get time. but when i repair for someone else, it is same day, or next day turnaround. so things are much easier for me when i just buy it.


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## adrenalinejunkie (Oct 17, 2010)

JL has an additional fee of $50 to slap on a serial number if an amp doesn't have one. Those stickers must look awesome when new.


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## shutmdown (Aug 24, 2008)

daveds50 said:


> i could, but i'd rather buy it.
> 
> im high volume, and quite busy. when i buy broken electronics, i dont have to time slot it in my schedule. i just repair it when i get time. but when i repair for someone else, it is same day, or next day turnaround. so things are much easier for me when i just buy it.


well if you can repair it how much would you charge?
also PM me an offer for the amp, maybe i'll just sell it to you...


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## daveds50 (Jun 10, 2011)

shutmdown said:


> well if you can repair it how much would you charge?
> also PM me an offer for the amp, maybe i'll just sell it to you...


 price on average for normal amps, your 300/4 included, is around $40-$70 plus return shipping. on your particular problem, it should be $55-$65. only the huge amps can get over $100. 
gotta think about the purchase price... 300/4's are not worth all that much.


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## shutmdown (Aug 24, 2008)

daveds50 said:


> price on average for normal amps, your 300/4 included, is around $40-$70 plus return shipping. on your particular problem, it should be $55-$65. only the huge amps can get over $100.
> gotta think about the purchase price... 300/4's are not worth all that much.


what would your turn aroudn time be?


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## daveds50 (Jun 10, 2011)

shutmdown said:


> what would your turn aroudn time be?


 has always been same day, or next day for the past 13 years. it all depends on what shipping service you use, and what time they deliver. 

the only time that does not apply, is when pallets of stuff are sent, or when people send huge boxes with multiple items... you guys know who you are !


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## shutmdown (Aug 24, 2008)

daveds50 said:


> has always been same day, or next day for the past 13 years. it all depends on what shipping service you use, and what time they deliver.
> 
> the only time that does not apply, is when pallets of stuff are sent, or when people send huge boxes with multiple items... you guys know who you are !


could i get your info to possibly send this amp to you in the next week or so.


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## daveds50 (Jun 10, 2011)

sure, PM sent.


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## lopezel (Aug 3, 2009)

Hey Dave! Good to see you over here... you still visit customtacos?

Dave is a great guy... does great work, is very reasonable on his prices, and has quick turnaround. He definitely knows his stuff and has always been more than willing to help me with any car audio questions.


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## daveds50 (Jun 10, 2011)

lopezel said:


> Hey Dave! Good to see you over here... you still visit customtacos?


 hey there ! i check into CT once in a while... but not much has been happening there lately.


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