Aquired this unit from a friend as a non-working unit. I can read electronics schematics, I worked in electronics for 30 years. Where can I buy a schematic for this subwoofer? It has some fairly high power resistors that are pretty cooked, but I don't know the value.
I realize that this is an old problem, but folks are still finding it on searches, so here goes.
Here are the two pages of schematics from KLH. I wrote to their tech department and explicitly asked for permission to share them here.
Here's the lower board, which has the power supply:
KLH ASW 10-120 subwoofer schematic - lower board
Here's the upper board:
KLH ASW 10-120 subwoofer schematic - upper board
I had a simular problem with the woofer making a loud crackling sound when turned on. It was the main caps that had blown. They were replaced but blew again. So, I decided to fix it myself. The problem was, after testing all the resistors, that 6 of them were bad. The main caps are going to be hard to find because they are so big. You can goto Mouser Electronics (an electronics distributer) and get all the stuff you need there. The problem I'm having is that there was a jumper wire going from a resistor on the high/low level input board to the transformer board. On the transformer side the wire broke and I do not know where it was connected. I need to find out.
This amp has a design flaw. They all fail rather quickly and then send 60 Hz HUMMMM tohe speaker, toasting it. The problem in my two sw10-120s is identical, both are rather new, and both failed at low volume after maybe a few hours of play. I see obviously blown power transistors or resistors. The heat detecting overload circuit doesnt do its job. The hmmmm occurrs when the unit is on, off, or on auto. Only unplugging it makes it stop. Chuck this amp and use the box as a passive 10 sub. What a piece of ****.
Had the same problem - completely agree - What a piece of ****
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I removed the upper board by cutting all the wires from it to the lower board. I then isolated the line input for the amp (lower board) wired in a 1/4 inch female and removed the speaker. Put in a 100 watt Speaker and now use it as an amp for my keyboard. This is the only use for the crappy KLH circuitry. Shame on them, they should know better.
Same model...my amp fried after a year. Good bass, poor reliability. Trying to get it fixed/replaced right now (amp), but seems to be a lossed cause. Wish I could help more (with your issue), but once it burns...well, it burns:(
Hello, I have the same unit and even though I havn't had any problems with it, i do have the instruction booklet plus some other "techie" type material that may help. My friends an engineer and had some I am completley new to this site and don't know how to get ahold of people directly
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same problem exact electronics cook resistors
KLH ASW10-120B subwoofer problem, risiters fried, where is a dealer in maryland, and where do i get parts
Exact same problem. It fried the power resistors!!
A crook sold me one saying that it works and since he had it with him at work and can't demo, and at $25, I took it home to try and it had crackling sound at any volume. The driver checked out OK, so it's the amp. Can the supposedly burnt resistor be found in Radio Shack?
i second the notion for a schematic. my power resistors look fine but two of the zener diodes look fried and i would love to be able to test them if i knew their rating.
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