KSW-12 with a blown amp (was told to post here)

[mntgoat]

I was given a Klipsch SW12 subwoofer which was broken. I replaced the fuse hoping that would be the issue but it still won't do anything when powered on. I'm guessing it has a blown amp, I would like to replace it, I believe it is this Klipsch model 118549. I only found one place online selling it for $140 but was wondering if there might be a better alternative? maybe even a cheaper one?

Thanks.

 

[Ian Finch]

If cheap is what you want, there are a lot of cheap plate amps suitable for subs at MCM electronics and Parts Express, for example. However, they are only certain sizes and those available may not suit that large looking panel. At $150 for the original, I think a direct replacement will still be a good deal, assuming you can't DIY repair or or convince someone to help out.
MCM Audio Select 200 Watt Subwoofer Amplifier Module | 50-6263 (506263) | MCM Audio Select
Subwoofer Plate Amplifiers in the Speaker Components Department at Parts Express | 332

 

[mntgoat]

If cheap is what you want, there are a lot of cheap plate amps suitable for subs at MCM electronics and Parts Express, for example. However, they are only certain sizes and those available may not suit that large looking panel. At $150 for the original, I think a direct replacement will still be a good deal, assuming you can't DIY repair or or convince someone to help out.
MCM Audio Select 200 Watt Subwoofer Amplifier Module | 50-6263 (506263) | MCM Audio Select
Subwoofer Plate Amplifiers in the Speaker Components Department at Parts Express | 332

I was considering doing the diy troubleshooting/repair but I'm not sure where to start or how difficult it might be, I've repaired things before, washers, dryers, that kind of thing but never something this complex.

 

[Ian Finch]

You're right to hesitate when looking at a 150W amp as first repair project. If a fuse that keeps blowing has you wondering, then you'll likely need quite a bit of coaching. Luckily the schematic is easily available.

Not much can be checked visually inside, short of looking for signs of violent flashes and fire. Many failures are invisible and you still have to identify and measure parts that have failed, like the ouput transistors and their drivers. When an amp is simply burning fuses, you need to power it up via an incandescent bulb, say 60-100W. That means building a bulb tester; an electrically safe connection to the bulb in a mains rated enclosure or even mod. an adaptor to plug a tablelamp into, such that the bulb is inline with the active lead. Earth and neutral should be unaltered. This way, even a dead shorted amp. can only pass the light bulb current as it glows normally. A working class AB amplifier will not cause more than a dull glow from the bulb and the fuse cannot blow but you may have sufficient voltage to identify failed output transistors.

You could do worse than follow troubleshooting procedures such as these, bearing in mind that it refers to basic DIY amps that have just been constructed. The principles are the same, though.
Consider that you will be up for probably > $30 in parts and freight and that is just the beginning, assuming you get the diagnosis right and order the right ones.

Rather than get immersed in details here, why not contact the module supplier and find out if they do refurbs. Maybe that will save you some if you decide not to mess with the electronics.

 

[mntgoat]

You're right to hesitate when looking at a 150W amp as first repair project. If a fuse that keeps blowing has you wondering, then you'll likely need quite a bit of coaching. Luckily the schematic is easily available.

Not much can be checked visually inside, short of looking for signs of violent flashes and fire. Many failures are invisible and you still have to identify and measure parts that have failed, like the ouput transistors and their drivers. When an amp is simply burning fuses, you need to power it up via an incandescent bulb, say 60-100W. That means building a bulb tester; an electrically safe connection to the bulb in a mains rated enclosure or even mod. an adaptor to plug a tablelamp into, such that the bulb is inline with the active lead. Earth and neutral should be unaltered. This way, even a dead shorted amp. can only pass the light bulb current as it glows normally. A working class AB amplifier will not cause more than a dull glow from the bulb and the fuse cannot blow but you may have sufficient voltage to identify failed output transistors.

You could do worse than follow troubleshooting procedures such as these, bearing in mind that it refers to basic DIY amps that have just been constructed. The principles are the same, though.
Consider that you will be up for probably > $30 in parts and freight and that is just the beginning, assuming you get the diagnosis right and order the right ones.

Rather than get immersed in details here, why not contact the module supplier and find out if they do refurbs. Maybe that will save you some if you decide not to mess with the electronics.

Thank you for all the info. I might contact the manufacturer to find out a refurbs. Part of me wants to just dive in a learn and part of me wants to just have a working subwoofer quickly.

 

[djk]

The BASH subwoofer amps from Klipsch are not a good first time repair project.

Buy a replacement amp, and repair the old one at your leisure.

 

[mntgoat]

So I just realized the fuse has been blowing every time I plug the thing in. Because of this I decided to unplug all cables going from one board to another and try it again. With nothing hooked up, so basically only the fuse and what looks like a transformer connected, the fuse didn't blow. I then hooked up the next connection which was to a board I am attaching pictures of. The fuse was blown right away. So I am posting some pics of it. I'm hoping I can replace that whole board but while looking at the pics I did notice something weird on what I'm guessing is a capacitor? (sorry been a long time since college). It almost looks like a chunk has burned off? I am posting some closeups. It feels rough to the touch.

Suggestions of where to go from here?

Thanks.