Kicker CXA1800.1 No Audio

Good morning,

I have this CXA1800.1 Kicker amp. First it was going in and out of protect and I replaced the caps in the Voltage Ladder Circuit, since I didn't have the 24v across ZD4. Now the amp powers up but I have no audio.
By reading the other post I see that I am suppose to have a sawtooth signal on pins 3 and 5 of IC11, I have a square wave. However; I do have a sawtooth on IC9 pin 1.
I have 91.3 volts rail. Measuring from power ground to drains of Q103 and Q203.
Any and all help will be appreciated!


  • Kicker CXA1800.1 Guts.jpg
    Kicker CXA1800.1 Guts.jpg
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For the benefit of others who may have similar issues, cajones found Q100,200. They are the muting transistors and may be the reason no audio is passing to the opamps. I suggested he remove JFET's temporally to see if this allows audio to pass through and replace them to finalize the repair. There may be other reasons other than failed JFET's and possibly the muting circuit that supplies the voltage to the JFET's.

Once we have cajones results when pulling the JFET's, we can go from there.
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1st question, don't need them, was just in case ever did. So I keep a file of part numbers with the different amps. So it is just for my info. Thanks.

2nd question, I am losing signal at ic1 when I power up the amp. As long as no power is applied I get a signal. I know that sound weird. I am using a BK Precision Function Generator and I am using a 50hz signal.

Ref from power grd to:
Pin 4.... 15.3vdc
pin 11.... -15.3vdc
When there is no remote gain control plugged in the 3.5mm socket connects R98-20.5K ohm across Pins 6 & 7 of IC3, which sets the gain of the opamp. I'm not sure what has failed but an open socket will open up the signal ground tied to R98 and affect the gain of the opamp. When plugging in the gain control and you may have overloaded the signal to the main board.Check socket, connections to R98, to Pins 6 & 7 of IC3 and around IC3. It's also possible there is a bad solder joint on R98,capacitors around IC or socket itself. I'm sure that the problem is in this circuit and close inspection and ohmmeter checks should weed out the lack of output[comment][/comment]

I got sound when I plugged into the 3.5mm port, but when I turned up volume not gain, it blew my test speaker.