Taramps DS 1200X4 2 ohms turns on but no audio

[Perry Babin]

To clarify, is this the original IC or is it one of the replacements?

Is the popping still on 2 channels?

Are you saying that, with those pads shorted that the CSD never charges? Even without the limiting?

 

[cush man]

Yes, this is the original, not the replacement. And the replacement was doing the same thing.

The popping is loudest on channels 1, it's present on the others but nowhere near as loud.

Yeah cap doesn't charge. Limiting current?

 

[Perry Babin]

What's the original state of that pair of pads (normal operation), bridged or open?

 

[cush man]

Open the cap charges, closed it doesn't. The original is open. I think it's a test point.

 

[Perry Babin]

JP tends to indicate jumper. I've never seen a jumper for testing that was meant to short but that seems to be the case here.

Is it correct that no outputs failed, originally?

Is the amp precisely as it was when you received it?

 

[cush man]

That surprised me too.

Yes that's correct everything is original and I haven't found any failed components so far.

Yes it's exactly as it was. The only thing I did differently was when I first looked at it a year ago the ceramic cap that has the -5V on it leading to the IC was reading a short, but when I replaced it nothing changed and outside the circuit there wasn't shorted. So I put it back in and there isn't any shorts.

But if it was bad, would there be -5V volts? The other end is connected to ground, I think.

 

[Perry Babin]

I don't see that as a problem unless the ±5v supplies are unstable when the amp tries to power up. Even then, having a problem on one channel only would be unlikely.

Is it possible that the output filter for that popping channel is defective? Defective cap or shorted inductor?

 

[cush man]

Oh okay.

Well it's made up of a diode, 2 caps, 1 polymer I guess and an electrolytic and the inductor. I didn't test all the electrolytic caps or the polymer ones. I did test the diodes and they seemed fine. But the inductor would be ready a short anyway?

I'm trying to send you a DM but it's not going through.

 

[Perry Babin]

You can email me:
babin_perry@yahoo.com

The inductor is only a short to a multimeter. It's far more complex when AC is applied. You could try swapping it to a channel with no problems to see if the problem follows the inductor.

 

[cush man]

Okay.

Okay so swap inductor.

 

[Perry Babin]

We're running out of options. All FETs are OK, the replacement IC did the same thing, all voltages are present... Try it.

 

[cush man]

Doing it now.

 

[cush man]

It looks like the inner winding is burned on the inductor that's in channel 1. WTF!

 

[cush man]

It turns out it's a bad inductor was the issue.