Crossfire C7 2000.4 nasty signal.

[rdiaz]

Hello everyone, I have with me a crossfire C7 2000.4, the amp works but the signal on the oscilloscope is nasty looks like some one also work on this amp before. Does someone knows what are the original mosfets are used on this amplifier power supply and output mosfets just want to make sure they used the correct parts. They have IRF3205s on the power supply and FB31N20D on the output section. Thank you.

 

[Perry Babin]

What do you mean by 'nasty'? Lots of full range class D amps have significant carrier leakage at the speaker terminals.

Are all 4 channels essentially the same?

 

[rdiaz]

Yes all the channels are the same.

 

[Perry Babin]

Is that really a 20v signal? The scope seems to indicate that it's set to 20v/div but the probe could be set to 1x.

Do the solder connections for the FETs appear to be flow soldered or hand soldered?

 

[rdiaz]

Yes sir it is a 20v signal. The probe is set to x10. Some one also fixed this unit before, is hand soldered.

 

[Perry Babin]

Have you tried contacting Crossfire to see if they would tell you what the outputs are supposed to be? And maybe a schematic?

Does this change when you connect a speaker?

Are there any open/out of tolerance components after the output filter?