Thursday, November 28, 2013
Tuesday, November 05, 2013
Had to "Fix" the KLH Subwoofer... again
Last night for about 2 hours, the subwoofer started making odd noises like it was receiving some odd RF interference. It's done it before. I remember pointing a cordless phone at it once, pressing a button on it, and it went off. It was annoying and even when I shut off the subwoofer, the sounds would persist. It was just as oddly coincidental that it would stop making noises when Bones finished airing.
This morning when I fired it up to check how it was doing now (and no longer making spurious noises) it had a decidedly less than desirable response. Choppy. Gritty. It wasn't a warm bass response. Great.
So I decided to open it up like last time and see if I spot those slightly out of spec solder points again. And I do, as well as testing with the chopstick to see how it responded. And it was the same kind of thing. So I fired up a soldering iron and touched the one spot I found and sure enough, the solder disappeared. So I find my solder and re-do that spot and check a couple of others. Plug it in and fire it up, tap the circuit board - no more of that sign of a component not connecting to the circuit. Nothing loose!
As a result of all that, I had to figure out how to re-calibrate the settings on the back of the subwoofer so that it was at an optimal level for crossover and volume. The technique I discovered was to set the Dolby receiver at a common volume level (50) and then play something with the DVD player to make sure the bass response is warm, clearly heard, and resonates in the room without sounding localized, something I remember reading in the instruction booklet.
I wonder if these KLH subwoofer circuits run hot because of seeing this one actually melting the solder in the smallest of margins to make it go out of spec. Either that or the solder melts too easily, or the components weren't soldered in that great to begin with. As I seem to recall, this subwoofer did this same thing years ago. It worked well, then went sputtering for bass response, before just not working at all.
This morning when I fired it up to check how it was doing now (and no longer making spurious noises) it had a decidedly less than desirable response. Choppy. Gritty. It wasn't a warm bass response. Great.
So I decided to open it up like last time and see if I spot those slightly out of spec solder points again. And I do, as well as testing with the chopstick to see how it responded. And it was the same kind of thing. So I fired up a soldering iron and touched the one spot I found and sure enough, the solder disappeared. So I find my solder and re-do that spot and check a couple of others. Plug it in and fire it up, tap the circuit board - no more of that sign of a component not connecting to the circuit. Nothing loose!
As a result of all that, I had to figure out how to re-calibrate the settings on the back of the subwoofer so that it was at an optimal level for crossover and volume. The technique I discovered was to set the Dolby receiver at a common volume level (50) and then play something with the DVD player to make sure the bass response is warm, clearly heard, and resonates in the room without sounding localized, something I remember reading in the instruction booklet.
I wonder if these KLH subwoofer circuits run hot because of seeing this one actually melting the solder in the smallest of margins to make it go out of spec. Either that or the solder melts too easily, or the components weren't soldered in that great to begin with. As I seem to recall, this subwoofer did this same thing years ago. It worked well, then went sputtering for bass response, before just not working at all.
