JBL LSR25R Slowly Stopped Working

[sharkmouth750]

Hello,

A while ago, our Powered 175watt JBL LSR25R's stopped working. Not overnight, just every single time we came in they were a little bit quieter until they were unusable. Any ideas on what could have gone wrong?

They have a power switch, volume potentiometer and four switch dip-switch. I've tried bypassing the potentiometer, but that did not seem to be the problem.

We did not abuse our speakers; they are 175 watt speakers but we only used them for in booth monitoring. We had them plugged into separate sound isolated ground circuits, and nothing else was plugged into those circuit.

I come here because I'm not a huge technical sound guy, but I was hoping to fix the speakers. I've seen some mentions of cleaning the circuit board, checking for loose solder joints and loose wires, but I don't really know what to do and what not to do. Since it was a slow decline, I'm thinking it might not be a bad solder joint, but that's just a thought. I would appreciate any suggestions on how to try to approach the problem.

Thanks,
Rob
P.S. Both speakers stopped working the same way. One started decline before the other, but both slowly quieted themselves until they were useless.

 

[DuckJordan]

Hello,

A while ago, our Powered 175watt JBL LSR25R's stopped working. Not overnight, just every single time we came in they were a little bit quieter until they were unusable. Any ideas on what could have gone wrong?

They have a power switch, volume potentiometer and four switch dip-switch. I've tried bypassing the potentiometer, but that did not seem to be the problem.

We did not abuse our speakers; they are 175 watt speakers but we only used them for in booth monitoring. We had them plugged into separate sound isolated ground circuits, and nothing else was plugged into those circuit.

I come here because I'm not a huge technical sound guy, but I was hoping to fix the speakers. I've seen some mentions of cleaning the circuit board, checking for loose solder joints and loose wires, but I don't really know what to do and what not to do. Since it was a slow decline, I'm thinking it might not be a bad solder joint, but that's just a thought. I would appreciate any suggestions on how to try to approach the problem.

Thanks,
Rob
P.S. Both speakers stopped working the same way. One started decline before the other, but both slowly quieted themselves until they were useless.

are you sure its the speakers? although it does sound like a failing amplifier to me. I understand for wanting to get them working again the only way i can think of (easiest) is to take out the internal amplifier in each make sure they have a crossover for the horn and mid/low woofer, and hook up a similarily sized amplifier to make sure its not a coil problem. Heat and powered speakers never have gone well with each other, so if its not the amp you may have two very dead cones and drivers.

 

[FMEng]

Hello,

A while ago, our Powered 175watt JBL LSR25R's stopped working. Not overnight, just every single time we came in they were a little bit quieter until they were unusable. Any ideas on what could have gone wrong?

They have a power switch, volume potentiometer and four switch dip-switch. I've tried bypassing the potentiometer, but that did not seem to be the problem.

We did not abuse our speakers; they are 175 watt speakers but we only used them for in booth monitoring. We had them plugged into separate sound isolated ground circuits, and nothing else was plugged into those circuit.

I come here because I'm not a huge technical sound guy, but I was hoping to fix the speakers. I've seen some mentions of cleaning the circuit board, checking for loose solder joints and loose wires, but I don't really know what to do and what not to do. Since it was a slow decline, I'm thinking it might not be a bad solder joint, but that's just a thought. I would appreciate any suggestions on how to try to approach the problem.

Thanks,
Rob
P.S. Both speakers stopped working the same way. One started decline before the other, but both slowly quieted themselves until they were useless.

From your description, my guess is a failing coupling capacitor. They are typically electrolytic types around 10 to 100 uF in size. I would suspect any that are close to a heatsink first. Often, the fastest thing to do is to replace all of the small value electrolytics at once. There probably aren't many in there and the parts are cheap. If you aren't good at desoldering and soldering have a competent repair tech do it.