HELP! subwoofer died!

[Scp53]

I have a friend with a JBL PSW D110 that died. He keeps replacing fuses

and they keep blowing(as soon as it gets a signal from the receiver, it

blows... grounding issue?).

I have pulled the amp and the C6 cap is blown and a few of the nearby

resistors got burned(when the cap blew). I was searching for help but

have found very little. I found this quote from a guy on a review

saying

"JBL suggests replacing this blown out C6 capacitor with a 10uF,

100V, NPE cap. They also suggest replacing the C24 cap with a 100nF,

50V cap, the R46 resistor with a 47ohm, 1/4 Watt resistor, and the R23

resistor with a 20kilo-ohm, 1/2 Watt resistor." Can anyone verify this?

My last question is if I solder the old parts off and put on the

"better" new ones, do I need to use really good solder? I was told bad

solder will induce noise into the circuit...? Other than that, Im

capable of replacing the parts.

Thanks for the help, scp53

ps- the guy would also buy a whole new amp if the JBL is going to blow

again(after I fix it)... maybe this is the way to go? have to modify

the box of course...

[TheEAR]

Only a tech who knows the amp well can confirm what you have read about the replacement parts. If correct then you need a 25W soldering iron witha fine point tip and not overheat the PCB(sourrounding parts).

Using irons in the 40W plus range is only needed for soldering larger pieces like thicker cables and small metal pieces. Make sure you preheat the iron and can work fast.Slow soldering is bad soldering.When parts are primed the job goes butter smooth.

You can use a powerful(40W plus)oron for smaller jobs as long as you are experienced and know how to solder.

Blown caps are ofdten the result of an improper chemical mix,cheap computer motherboards suffer alot from blown,leaky caps.

[Scp53]

thanks for the reply. so, do you think this amp will have more problems down the road? As I said before, maybe modifying the box to fit different amp is the way to go? PE has 240 watt class AB amps that are very reliable. $120 plus shipping. But Im not sure the sub is worth spending that much on. I hooked up my 250watt PE amp and honestly, this subs is definetly boomy and lacks extension(could have guessed that based on a small short port in a decent sized box). Besides that, the box build quality is poor(1/2inch particle board) and the woofer used is nothing special. Its msrp was $350 originally 5 years ago when he bought it. Someone help me decide if this sub is worth fixing...

btw, just to note theEar, Im no expert at soldering. Im ok,(modified my own amp one time, build a multi test from scratch too) and those turned out ok. BTW, I dont think you mentioned what type of solder I should use? anything special?(figuring I fix vs replace the amp?)

thanks again, scp53

[TheEAR]

I use Deans solder,contains %2 silver.Great for general soldering of electronic components and wires.I use it for all my soldering jobs.

Using the soldering iron well is an art,I saw too many botched soldering jobs,overheated parts or cold joints.Both bad

To become adept you need a good deal of practice and understaning the correct way to solder.Also a steady hand is a must.I repaired a good few boards removing CMOS chips and the customer did not belive me when he saw the work.

Will you have problems after? I cannot tell I would have to examine the amp board,could be only bad caps,then if you replace them with the new one it should all be fine.Is there another part causing tthe failure? Often like on MOBOS its just faulty caps,inflating,leaking and doing a mess.

[Paul]

You can change or modifiy any type of part you like,But make sure you have the right guy that knows his stuff,As for solder a good flux core can be used like i do,I also use a pyro pen for all my solder jobs.I just have more control of my work with out the worry of a cord dangling from the end.you can purchase them from Weller and other company's.

[DrWho]

Why don't you just email the tech guys over at JBL and see what they

have to say? They're usually pretty good about responding to such

things (at least their pro audio division is).

As far as soldering, the basic stuff you can get at radioshack is good

enough. Just make sure you get the right diameter for the job as it

makes the solding infinitly easier. The higher lead content you get,

the easier it is to melt the solder, but the less conductivity it will

have (so go with a high silver content). But more important than the

solder you use is making sure you don't end up with a cold solder

joint. If it ain't shiny, then you did something wrong.

Btw, you run a higher risk of causing damage with a too cold iron than

a slightly too hot one. You just gotta be quick with the hotter irons.