Wharfedale RS10 subwoofer is restarting at high volume

[drakejest]

So i have a Wharfedale RS10 5 in 1 taken out from storage (for about a year). The subwoofer has been misbehaving lately. So the subwoofer is an active subwoofer that needs to be connected to the wall and takes in a subwoofer signal from an amp.

So at 50 (out of 99) volume, i could not feel the subwoofer, very quiet it might as well been off. At 75 volume is where i like it, the base is strong, but here comes the problem. With songs that have a lot of base in them, after a while the display will start to flicker (the base is still there) like its not provided enough power. At 85 volume is a bit more crazier, again the base feels strong and when the heavy continuous base of the song comes the subwoofer flat out shutdowns and restart. It will not play anymore, unless it is restarted by turning off the wall power switch and turning it on again.

Given that i suspect a blown capacitor or the transistors are failing. It also does not sound like a blown speaker though it can kick, but not for long, like its not being fed with enough power. That is just my opinion though. I would like to attempt to repair it, i have experience in electronics and comfortable soldering/de-soldering stuff, but this will be my first time repairing audio electronics. Glancing at the circuit there doesn't seem to have a component that catastrophically failed.

Has anybody experienced this before? What could it possibly be? Before i begin dismantling the stuff i would to hear your guys opinion first

 

[cademan]

Hi and welcome!

This may not be your problem but it is possible that a part could be loose or a cold solder joint could need resoldering. Not being solid, the bass could be vibrating enough to cause intermittance somewhere on the circuit board.

Please do not automatically assume capacitors or transistors as a problem before you troubleshoot the circuit.

 

[Powertech]

You say it shuts down and you have to cycle the power to restart it. Are you sure it's not overloading at high volume and triggering it's overload protection circuit?.

 

[Lavane]

Would it have a thermal overload device? I have an integrated amplifier with them. The output transistors get too hot the amp shuts down.
They usually look like a ceramic brick like resistor attached to the heat sink.
I know poly switches used to protect tweeters can degrade over time and the resistance changes. In the one amp I have, it's supposed to be able to use one pair of 4 ohm speakers, or two pairs of 8 ohm speakers, but if I do use two sets of 8 ohm speakers, or one pair of 4 ohm speakers the thermal protection will kick in after about 20 minutes.