Sundown SAE-1500D

[caraudioguy2100]

Amp is producing rail and regulated voltages .

Amp has output but it’s very distorted like someone is farting through the test speaker .

Any idea on where to start looking since everything I’ve checked so far tests fine

 

[Perry Babin]

What's the part number of U108(?) near the output driver IC?

 

[caraudioguy2100]

74HC02D

 

[Perry Babin]

Is the audio out of all of the preamp ICs clean?

Does it ever lose r-r oscillation when it's doing what you described?

U1 and Q1?

 

[caraudioguy2100]

I will have to get a new probe for my scope in the morning somce o believe it’s bad the scope doesn’t do anything at all I believe the probe went bad .

Here’s some more pics of the opamps and the transistor

 

[Perry Babin]

To test the scope, you can run a jumper wire from the test point to the center conductor of the scope input.

 

[caraudioguy2100]

I tried the jumper wire on the scope and it seems to tigger with the wire but not the probe .

I might have a spare probe around I will
Check and post back

 

[Perry Babin]

They are $5 each. Buy at least 4 at a time.

 

[caraudioguy2100]

The amp loses rail to rail oscillation when driving a signal into the amp

 

[Perry Babin]

Is the oscillation dropping out on the input pins of the driver IC?

 

[caraudioguy2100]

Do you happen to know what driver ic they are using ?

The one in the amp is defaced .

So I know which pins are the input pins

 

[Perry Babin]

An IR2113?

 

[mnhiphop101]

Ir2113 is correct

 

[caraudioguy2100]

It will lose oscillation on the driver ic’s output pins as well .

I get a square wave on all of the speaker terminals with no load is this normal ?

 

[Perry Babin]

The scope settings are VERY important for the image to be of any use.

 

[caraudioguy2100]

This is what I get on both positive and negative speaker terminals
With no load and no signal .

Scope set to 10us .5 volts/div

 

[Perry Babin]

You're using the wrong ground to be using such a low vertical amplifier setting. Use the negative speaker terminal.

Vertical amplifier setting that low are rarely useful on class D amplifiers. They all pass carrier noise to the output, some more than others.

 

[caraudioguy2100]

So I should ground the probe to the negative speaker terminal and set scope to 10us 2 or 5 volts div?

 

[Perry Babin]

What are you looking for?

 

[caraudioguy2100]

I’m just wondering if it’s normal to have a square wave on the output terminals with no signal .

With just power ground remote hooked up I bet a square wave on the output terminals was wondering if that’s normal ?

Trying to track down the issue with this amp