Hi All, I picked this sub up for less than a pack of smokes from a garage sale to use in my home office. When I first turned it on, it worked just fine. A week later when the green light is on the first thing that happens is the woofer come out slowly then goes back in to its resting position then it makes what I can only describe is a low frequency crackle. This happens when it is playing music, not playing music, RCA plugged in or not plugged in.
(Edit) now when I turn it on the light is red and the woofer comes all the way out then goes in and the light turnes green. Then it turns red and does the same again and again.
I pulled the amp this morning and saw no issues with a visual inspection. No bulging caps or burned PCBs.
Any ideas what the problem might be?
Even with the crackling, it is a fine sounding sub which fills in the 70hz and lower that my desk top speaker can produce.
I know this is not a high end amp but it works for my purpose and if I can fix it, I'd like too.
(Edit) now when I turn it on the light is red and the woofer comes all the way out then goes in and the light turnes green. Then it turns red and does the same again and again.
I pulled the amp this morning and saw no issues with a visual inspection. No bulging caps or burned PCBs.
Any ideas what the problem might be?
Even with the crackling, it is a fine sounding sub which fills in the 70hz and lower that my desk top speaker can produce.
I know this is not a high end amp but it works for my purpose and if I can fix it, I'd like too.
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It has a standard class D amplifier built in. Check the rails for the correct voltages, there are four. Does the amplifier oscillate correctly? what have you got on the output FETs, voltage wise? Check the fault finding flow chart in the service manual. Page 12.
Thanks Jon. I'll do that. I've never been very good at diagnosing. Maybe I can use this as a learning opportunity.
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