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What is wrong with subwoofer line filter circuit board?

I have a Klipsch 10" Subwoofer with a built in line filter on the signal. When powered on and fed a signal I get nothing. I've tested feeding the unit multiple signls with no results. Directly giving the speaker a low HZ signal confirms to me that the speaker is not the issue. I don't see any capacitors that look buldging or any resistors that looked cracked. There is a transformer looking piece that i believe has leaked and could be the problem. I have a multimeter, but don't know how to test that compoenet. I also don't how to determine what that component is, but i would think i could find a replacemnt part at mouser.com Can anyone help solve this?

Board Details - BASH - INDIGO CANADA 600134 REV:2
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danengle

We'll probably need more information/background. When did the unit stop working? Can you think of anything significant such as a brown out condition or power fluctuation/spike that led up to the speaker failure?

I am assuming the unit is no longer under warranty. If it is, I would strongly recommend contacting their warranty department. Based on the pictures and information listed, I'm not seeing anything that may be the cause. I would look closely for any scorched connections/components. If you have a multimeter/continuity tester, check for continuity between the plug and AFTER the fuse/circuitbreaker (it looks like the fuse/CB is the round item right above the plug.

shawnkimble

ASKER

I have no idea when it stopped working, I don't use it a lot. I've checked the fuse, the fuse is fine so I don't think it has a power spike issue. Its older than 2 years, so warrantee doesn't apply, and I don't want to waste $ on shipping such a heavy object back when I know I can solve it myself.

Before I noticed when plugged in the speaker makes a click every so often when no signal is attached, but currently I'm unable to reproduce that. This made me think it was a capacitory discharging, but again it doesn't seem to be doing that now.

Can you properly test the capacitors when they are on the board?

shawnkimble

ASKER

I've also tested the following items on the board:

Top of Board 1
- Input AC power at the point of entry on the board is 119V AC

Top of Board 2
- 470uF 200 WV Center CAP with power on measures 162V DC, and power off 485 uF
- 470uF 100WV Right CAP with power on measures 109V DC, and power off 400 uF - This seems to operate out of tolerance, but i don't know if that really matters.
- There is no continuity between speaker outputs
- There is no continuity between either speaker output and either speaker input (Center of RC Jack) - Both while on or off

Bottom of Board
- The outer jacket of the L& R RC Jack go to ground, and that appears to be the design of the circuit.

ASKER CERTIFIED SOLUTION

danengle

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Callandor

You can diagnose capacitors using an ESR meter http://www.anatekcorp.com/testequipment/esrcompar.htm. Some capacitors can be tested onboard, but others have to be isolated.

shawnkimble

ASKER

I think I'll just replace the large Caps and see what happens. I'll post an update if that solves the issue.

Callandor

If you do, try to use higher-temperature capacitors, as they are succeptible to drying out if they are in a hot location. For example, there were 85C capacitors in a projector that eventually failed due to heat, and it was recommended to replace them with 105C models.

BTSTech

I have the exact same unit. Mine works but the output is very low and very distorted. The speaker works fine on another amp. Need schematics very badly. Please help :)

shawnkimble

ASKER

mirclbob

Try checking the MOSFETs on the large aluminum heatsink board. I believe one in voltage control and others are power amp. This is a current sensing amp.