I had a Kicker which had a 15V regulator resistor blown apart. R173, R174, R176 are also all open/cracked.
It can drive a lot of power, but its heavily distorted unless I turn the volume mostly down.
What is weird is when bending/twisting on the board i could make it produce a very loud hash noise, and then sometimes it would come out perfectly clean with no faults in the audio.
So, from what I learned on the CX600.1 I went ahead and resoldered the whole power output stage. No change in behavior. I decided to inductance check and ring check both output inductors, and they match.
The fact I can bang on the PCB and get the behavior to change (sometimes) leads me to believe theres an intermittent connection somewhere but im just not finding it. its hard to track down the search area without a schematic.
Posted a screenshot of the output from the amplifier, that is supposed to be a sinewave but as you can see, its anything but. All 4 output transistors have a PWM drive waveform.
It can drive a lot of power, but its heavily distorted unless I turn the volume mostly down.
What is weird is when bending/twisting on the board i could make it produce a very loud hash noise, and then sometimes it would come out perfectly clean with no faults in the audio.
So, from what I learned on the CX600.1 I went ahead and resoldered the whole power output stage. No change in behavior. I decided to inductance check and ring check both output inductors, and they match.
The fact I can bang on the PCB and get the behavior to change (sometimes) leads me to believe theres an intermittent connection somewhere but im just not finding it. its hard to track down the search area without a schematic.
Posted a screenshot of the output from the amplifier, that is supposed to be a sinewave but as you can see, its anything but. All 4 output transistors have a PWM drive waveform.
If you don't get any other help, post a photo of the board.
If this is a half-bridge amplifier, ground the scope to the negative speaker terminals. Does that give you a better scope waveform.
If this is a half-bridge amplifier, ground the scope to the negative speaker terminals. Does that give you a better scope waveform.
If the outputs aren't being driven, this may be normal. Does the scope show what you'd expect on the preamp supply voltage and the various audio signals?
Well thats the waveform when the amp is operating fully, and driving the speaker. (its the same without teh speaker). That should be sinusoidal and not whatever that is. That malformed sinewave is the fault mode and you can hear it in the audio, sounds like bad clipping.
Also when it goes into hash mode it will just look like a bunch of noise on the scope and it fries those resistors again.
I also decided to spray the TL072 IC area (I assume its the integrator) with freeze spray and thats when it went from malformed sinewave back into a hash (unstable oscillation) again.
Heres some pictures of the amplifier. I pointed out the area in which i hit with freeze spray that drastically changes the behavior of the amplifier including introducing the fault modes
