Kicker 43cxa12001 Output trouble possibly.

[rhempz01]

So i am in the process of repaired a few dozen of these amplifiers. This one has good output transistors, rail.and regulated voltages are present. I have 25.46vdc on the speaker terminals?
replaced all the caps c61_c63 100nf 100v capacitors.
all three coresponding diodes 12-24-12v

 

[Osvaldo de Banfield]

If the output transistors had blown, you need to review the entire amplifier to see what more had blown. Start with previous stages, direct coupled, like resistors and diodes. Caps rarely become short circuit with a massive component failures.

 

[PapaZBill]

Is the amp in protection? Do you have drive to the output mosfets? It sounds like the PWM circuit may have failed.

 

[PapaZBill]

Check the waveform at C43, near Q25. One side should have a sawtooth/triangle waveform.

Do you have the ZD3,ZD4,ZD5 voltages, 12v-24v-12v?

 

[rhempz01]

yes the voltage ladder i repaired 12-12-25.86vdc. still i have that voltage across the speaker terminals? 21.85vdc
audio is present, but distorted. Or off somehow?
i checked my 16r 27r r175 and d33-34.

 

[rhempz01]

at speaker terminal 10x.
input is 40hrz ampl. 4v duty. cycle 50.% (same signal i always use)

 

[rhempz01]

has a very buzz like sound to the sound coming out of the amplifier. maybe one of the output drivers? irs2957s?

 

[PapaZBill]

at speaker terminal 10x.
input is 40hrz ampl. 4v duty. cycle 50.% (same signal i always use)

Please clarify. Are you describing the input signal as 4Vp-p, 40hz?
Is this a sinewave or a squarewave? How does the 50% duty cycle apply?

What is the Rail Voltage? The squarewave drive voltage to the output mosfets will be half the rail voltage, due to 50% Duty Cycle.

A screenshot of the waveform before and after the output coils with and without signal would be helpful.

 

[rhempz01]

yes its the input sine wave. 40hrz 4v.

 

[rhempz01]

74.2vdc rail

 

[rhempz01]

leg 1 of q103

 

[rhempz01]

while trying to get the screen shots i noticed that the amplifier was back into protection. Only remote and ground were applied.

 

[rhempz01]

before output coils

 

[rhempz01]

after the second inductors.

 

[rhempz01]

at the rca inputs.

 

[rhempz01]

not sure if these are the correct point of measurement you were refering too. if you give me a location i will post another.

 

[PapaZBill]

Is there still an issue here?

while trying to get the screen shots i noticed that the amplifier was back into protection. Only remote and ground were applied.

 

[PapaZBill]

Do you still have a square wave at this test point?

leg 1 of q103

 

[PapaZBill]

I'm not sure whats going on here, you should have a square wave if you have a square wave at Q103. I'm unclear what pin 1 is. Can you identify if this is the gate or the source. The Drain would be the middle pin.

before output coils

 

[PapaZBill]

If you look at the inputs to L101 and L201 you should see a squarewave.