Kicker CXA300. 4 pulsating protection issue.

Despite changing all the smd Co. Points I know of on these amplifiers,
4.7r, 0r, 4401-4403, both the driver card and the power curcuit.
The Amp remains in pulsation protection. I have removed all of the protection 10k resistors one at time.
Protection always remained the same, pulsation about. 7amps of current. Never turning on?
 
Correction D52 not DP52. D52 hangs off of IC3-LM358 comparator monitoring the B+ line and sends a error signal to U14-Pin 16.

Replace DP4 and D52. Look at the DC voltage at the anode of D52, same as IC3-Pin 7. Normally this voltage will read low near 0 volts.

If it reads high remove the mosfets Q24,25,28,29-IRFZ46N. Check the DC Volts around U14 and look at waveforms at Pins 5, Pins 9 & 10. Post your results.
 
Pins 5,9,10
 

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Tl494c voltage.
1.) . 883
2.) 3.693
3.) 0.054
4.) 0.029
5.) 1.445
6.) 0.001
7.) 0.000
8.) 0.000
9.) 10.21
10.) 5.23
11.) 0.008
12.) 13.19
13.) 4.891
14.) 4.872
15.) 4.871
16.) 4.117

As soon as I add the fets the pulsing starts, using irf3205's still have the 100R gate resistors, should I lower the resistance to say 47R?
 
Last edited:
Tl494c voltage.
1.) . 883
2.) 3.693
3.) 0.054
4.) 0.029
5.) 1.445
6.) 0.001
7.) 0.000
8.) 0.000
9.) 10.21
10.) 5.23
11.) 0.008
12.) 13.19
13.) 4.891
14.) 4.872
15.) 4.871
16.) 4.117

As soon as I add the fets the pulsing starts, using irf3205's still have the 100R gate resistors, should I lower the resistance to say 47R?

The voltages you listed for Pins 8 through 11 can't be correct, considering the waveforms you posted. But based on those waveforms the power supply is working. I'll have to get back to you about the gate resistor values, but the 100 ohm resistors shouldn't cause the amp to pulsate.

Check the resistances between speaker and power GND's
 
OK, now I have been through the entire curcuit. No failed components. Drive is good. I removed all the outputs and lifted the output protection resistors. R33, R34, R88, R89. Powered up the amp, current. So I go to Check the ps fets one is shorted. I remove it and power it up again. Current. Removed them all drive is 100% Good 30khrz square wave. All resistors and capacitors check good. So I'm leaning towards the transformer has a short somewhere.
 
OK, now I have been through the entire curcuit. No failed components. Drive is good. I removed all the outputs and lifted the output protection resistors. R33, R34, R88, R89. Powered up the amp, current. So I go to Check the ps fets one is shorted. I remove it and power it up again. Current. Removed them all drive is 100% Good 30khrz square wave. All resistors and capacitors check good. So I'm leaning towards the transformer has a short somewhere.

I'm assuming the rectifiers at location BR1 and BR2 are not shorted.

Also, to be sure the current draw is caused by the transformer and not something in the output stages, remove BR1 and BR2 and check again for current draw.