Amp has some sort of problem. 
When the amp is in the off position it will thump at random intervals. Maybe every 30 seconds or so. When the amp is turned on the thumping stops but does not play audio.
Can anyone offer any help and/or troubleshooting for this amp?
Fuse is missing in photo, but yes, it was installed when testing.
Much higher res photos are available if they will help.
When the amp is in the off position it will thump at random intervals. Maybe every 30 seconds or so. When the amp is turned on the thumping stops but does not play audio.
Can anyone offer any help and/or troubleshooting for this amp?
Fuse is missing in photo, but yes, it was installed when testing.
Much higher res photos are available if they will help.
Man I would not trust that amp plugged in for very long. I don't know off hand what the problem is. I would check parts for excess heat while plugged in, on or off. Check DC voltage on the output of the board that the power cord comes into. Anything? Move on to the three big black wires on the outs of the other boards. What year is this amp from?
Looks like a couple burnt resistors in the bottom picture. Fourth to the left of the right trim pot and top left,second one in. Rust isn't a great sign either. I see some 99 date codes on one of the circuit boards. Those were the days of the counterfeit capacitors. You should likely go through all the resistors and see if they are still close to spec and check all electrolytic caps to start. Almost sounds like some kind of RC circuit happening when it's off. There may be corrosion on the wipers on all the trim pots too.
There are many cheap ESR Cap checkers that can be used in circuit. They work fairly well unless something low resistance or another cap is paralleled with the cap. Usually you can figure out what the resistors used to be by looking at the other channel. No such luck here obviously. The burnt ones will likely be fairly low resistance.
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It seems like yet another brand of sub amp has failed to live a long life.
Frankly, those SMPS designs are inexpensive (cheap chinese junk) and should be tossed, something I've done already with a Polk sub.
Replaced with a linear supply powered type with much better performance and reliability.
Frankly, those SMPS designs are inexpensive (cheap chinese junk) and should be tossed, something I've done already with a Polk sub.
Replaced with a linear supply powered type with much better performance and reliability.
agreed, get so many of those crap asian sub amps in from so called 'hi end' brands
I would source replacement board or inform customer to bin unit
Whenever I get one of those cheaply made SMPS sub amps I rip 'em out and source my distributor Apex Jr for a solid "analog" replacement.
ApexJr Subwoofer Amps
Hi all, I also have problem with this particular board but instead of Klipsch, it's the Pioneer TZ-F700 speakers. The 30VDC (CD+ and CD- ) supply voltage on this board jump up to over 150V after half second everytime I flipped the switch thus cause DC (about 8VDC) on the speakers outputs. IF anyone have the schematic or advice, I would really appreciate it.
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