I have a 2017 kicker CXA1800.1d with a low audio problem. I am not knowledgeable with fly-backnpoeer suppy systems. However I have +-15 on R23-R24, drive is present on both output and power supply mosfets just low audio? Any help anyone can give me would be most welcomed.
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I don't have anything on this amp but on similar amps, you have to be careful of charged rail caps, well after power is removed. The rail caps can charge, to 12v, with no remote voltage. Check for voltage measured directly across the rail caps to see if it's a problem with this amp. If it is, discharge then EVERY time you power it up.
Are you getting rail-rail oscillation on the output FETs?
Are you getting rail-rail oscillation on the output FETs?
Probe pins 3 & 5 IC11-LM393 with your scope. You should see a fully formed sawtooth.
If so, then check to see if you have signal at the two resistors R150 & R250-6.8k ohm which feed IC10-TL072.
Use a 50hz test tone if possible. Post the screen shot for either waveform.
If you do not see the 50hz test tone at IC10, start at the RCA's and follow the signal through the preamp IC1 through IC6.
There are a couple of 270nf blue box TH caps in the preamp stage that pass audio between opamps, sometimes they have cold solder and need to be reflowed. I haven't seen this on an CXA18001 but it's worth noting. Also the Remote Gain Control's 3.5mm port has a similar cold solder issue and will effect IC3's gain and will not pass signal
If so, then check to see if you have signal at the two resistors R150 & R250-6.8k ohm which feed IC10-TL072.
Use a 50hz test tone if possible. Post the screen shot for either waveform.
If you do not see the 50hz test tone at IC10, start at the RCA's and follow the signal through the preamp IC1 through IC6.
There are a couple of 270nf blue box TH caps in the preamp stage that pass audio between opamps, sometimes they have cold solder and need to be reflowed. I haven't seen this on an CXA18001 but it's worth noting. Also the Remote Gain Control's 3.5mm port has a similar cold solder issue and will effect IC3's gain and will not pass signal
This amp doesn't require a sawtooth to oscillate.
Measure the DC voltage from power ground to the cathode of ZD5-12v, ZD4-24v and ZD3-12v.This is a voltage ladder supply for IC9,IC10,IC11.
If any of these zeners show less than expected the problem most likely is a failed 100nf sm capacitor in parallel with the zeners. C61,C62 & C63 are each across two of the zeners and will cause the voltage drop to be significantly low in that parallel bank and shutting down the IC. My guess is IC9 the sawtooth generator has no operating voltage.
Measure the DC voltage from power ground to the cathode of ZD5-12v, ZD4-24v and ZD3-12v.This is a voltage ladder supply for IC9,IC10,IC11.
If any of these zeners show less than expected the problem most likely is a failed 100nf sm capacitor in parallel with the zeners. C61,C62 & C63 are each across two of the zeners and will cause the voltage drop to be significantly low in that parallel bank and shutting down the IC. My guess is IC9 the sawtooth generator has no operating voltage.
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