Orion cobalt CB1500.1D

[imraneesa]

Hi,

The amp came with blown output mosfets and driver transistors. Changed all now I am having good low side oscillations but on high side the oscillations are not correct. Attaching the pictures.

 

[Perry Babin]

What happens if you connect a load across the speaker terminals?

 

[imraneesa]

What happens if you connect a load across the speaker terminals?

When load connected I got good oscillations for 1 second then it went into protect and trying to pull current. Using current limiter so it stayed near 1.7amps and protect light flickers.

 

[Perry Babin]

Remove the rectifiers and re-check the drive signals.

 

[imraneesa]

Remove the rectifiers and re-check the drive signals.

After trying with the load and after it gone into protect. Now without load there is no oscillations. I removed rectifiers and still no oscillations and this is without load on speaker terminals.

 

[Perry Babin]

Do you have oscillation on the output pins of the driver board?

Is the mute line dropping fully to ground?

 

[imraneesa]

Do you have oscillation on the output pins of the driver board?

Is the mute line dropping fully to ground?

No oscillations on driver board now. Before applying load yes I had oscillations. 3 pin remaining at 3.2v. Even after removing remote.

 

[Perry Babin]

That has to be VERY near 0v for the output drive to be present.

Is it producing drive to the power supply FETs?

 

[imraneesa]

That has to be VERY near 0v for the output drive to be present.

Is it producing drive to the power supply FETs?

Without rectifiers there is no high side oscillations. Only low side oscillations. But from driver board I have oscillations on two pins. Also both the optocoupler has oscillations on pin 6

 

[Perry Babin]

The high-side is likely floating but it could be that there is no signal.

With no rail voltage, you can connect the scope ground to the high-side source. Connecting a load across the speaker terminals will also generally allow you to see the signal if it's floating.