Crossfire amp help please cfa-602

[Perry Babin]

Have you been using a limiter?

If so, try it without the limiter but be careful. It may draw excessive current. Clamp all power supply FETs to the heatsink before applying power.

 

[joesch1999]

Amp still goes into protect takes longer, only thing that gets hot is the z44's I checked those with my scope they all look great. Perfect actually, but the amp is pulling about 9.5 amps at idle before it goes into protect.

 

[Perry Babin]

Do all of the power supply FETs get hot?

 

[joesch1999]

yeah everyone of them do, power caps get hot after a while to but I took all of those out and checked them at there rated voltage which I think was 50 volts if I remember right did a leakage test on them as well, they were fine

 

[joesch1999]

there is four diodes in spots d801, d802, d803, d804 two negative and two positive they are fine as well, two of them send voltage to the two caps right next to them and two go back to the gray body and black line diodes d106 and d107 not sure what kind of diodes those are.

 

[Perry Babin]

What's the DC voltage across the B+ and ground terminals?

Post a photo of the gate signal on the power supply FETs. If all are the same, only post one. If they're all different, post one from each bank.

 

[joesch1999]

+21 volts all terminals red lead on b+ black on terminals, waiting on camera battery be about twenty min

 

[Perry Babin]

21v on the power terminals of the amp?

 

[joesch1999]

no they are at 13.8 volts thought you were talking from the battery to the speaker terminals

 

[joesch1999]

http://www.diyaudio.com/forums/gallery/showphoto.php/photo/6511/ppuser/162317

Here is the trace of the n fets all look the same

should I remove those drivers for the 718's and power the amp up maybe eliminate some possibilities

 

[Perry Babin]

That's the drain. I need to see the photo of the gate drive signal.

 

[joesch1999]

Picture_003 - My Photo Gallery

here's the gate all the same

 

[Perry Babin]

If that's the gate, that's a serious problem. Post one of the signal on pin 9 of the power supply driver IC (TL494/594?).

 

[joesch1999]

I did the gate at the .5 volts division

 

[Perry Babin]

With the scope set to 0.5v/div, if you touch the probe to the B+ terminal of the amp, does the trace deflect off of the display?

If not, how far does it deflect?

Are you going to post a photo of the waveform on pin 9?

 

[joesch1999]

yeah it does deflect off the scope yes will be posting in a few min

 

[Perry Babin]

Why did you use 0.5v/div for the gate?

 

[joesch1999]

because I am only gettting .96 volts on the gate there is a short somewhere, here is the gate pin nine is flat unless i go way down on volts division.
Picture_004 - My Photo Gallery

 

[joesch1999]

I was assuming it was because of the positive voltage on the 3 bjf, or whatever was causing the problem in the audio section

 

[Perry Babin]

Post the DC voltage on all 16 pins of the power supply IC. Place the black meter probe on the amplifier's ground terminal. Place the red meter probe on the point where you need to measure the voltage.

Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16: