MTX Audio

[imraneesa]

Hi,

This amp has all the wave forms and also square wave on one side of inductor but other side no sinewave at all. Picture of the amp attached. Sinewave is reaching driver board.

 

[Perry Babin]

Is the square wave modulated when you drive a signal into the amp?

 

[imraneesa]

Is the square wave modulated when you drive a signal into the amp?

i drove 100hz and it was showing 97hz and 100hz. and what exactly is modulated mean.

 

[Perry Babin]

Modulation is when a square wave changes pulse width in relation to the input signal. With no modulation, it's a clean square wave. With modulation, it's mostly blurred.

This is a power supply being modulated. It's different because it's always less than 50% but you get the idea. It's only 640x480 resolution so if viewed full screen, it looks awful.

http://www.bcae1.com/temp/audioandpowersupply01.avi

 

[imraneesa]

Modulation is when a square wave changes pulse width in relation to the input signal. With no modulation, it's a clean square wave. With modulation, it's mostly blurred.

This is a power supply being modulated. It's different because it's always less than 50% but you get the idea. It's only 640x480 resolution so if viewed full screen, it looks awful.

http://www.bcae1.com/temp/audioandpowersupply01.avi

There is no modulation. It is just a square wave 110khz frequency.

 

[Perry Babin]

How low is the muting voltage going on the driver board header?

The pin configuration should be the same as the SLA1500 but it has two fewer pins.
http://www.bcae1.com/temp/SLA1500.pdf

 

[imraneesa]

How low is the muting voltage going on the driver board header?

The pin configuration should be the same as the SLA1500 but it has two fewer pins.
http://www.bcae1.com/temp/SLA1500.pdf

Voltage is 0v

 

[Perry Babin]

You stated that you had audio on the driver board. How far into the circuit does the audio go? Where is the last point where you see the audio?

 

[imraneesa]

You stated that you had audio on the driver board. How far into the circuit does the audio go? Where is the last point where you see the audio?

Upto the 5th pin of lm6172.
Output pins of same lm6172 is 100khz square wave.

 

[Perry Babin]

Is the 6172 defective? I don't see how the input pin of the op-amp could have signal on it without it affecting the output.

 

[imraneesa]

Is the 6172 defective? I don't see how the input pin of the op-amp could have signal on it without it affecting the output.

I dont have that to replace and check is there any replacement I can use?

 

[Perry Babin]

The 6172 is a high-speed op-amp. Others may work but may not perform as well. They may be sufficient for testing. Don't damage the 6172 if you try changing it unless you regularly order parts.

 

[imraneesa]

The 6172 is a high-speed op-amp. Others may work but may not perform as well. They may be sufficient for testing. Don't damage the 6172 if you try changing it unless you regularly order parts.

No change when the opamp change. Still no output.

 

[Perry Babin]

What do you have on pins 6 and 7 when you have audio on pin 5?

Do you see any modulation on pin 7 when you have audio input?

 

[imraneesa]

What do you have on pins 6 and 7 when you have audio on pin 5?

Do you see any modulation on pin 7 when you have audio input?

When I replaced the opamp the amp going into mute.
I am having 3.6v on mute pin.
I put back 6172 and it is still going into mute.



Pin5 has sinewave pin6 triangular wave and pin7 square wave but no modulation

 

[Perry Babin]

Is the square wave perfectly sharp? If you use audio instead of a sine wave, does the square wave look different?

 

[imraneesa]

Is the square wave perfectly sharp? If you use audio instead of a sine wave, does the square wave look different?

Attaching square waves with and without audio.



Waveform changing with sine wave and normal audio.

 

[Perry Babin]

You have modulation. If you have that at the input to the inductor and no audio on its output terminal, you likely have a broken connection on the inductor.

 

[imraneesa]

You have modulation. If you have that at the input to the inductor and no audio on its output terminal, you likely have a broken connection on the inductor.

Now it going into mute.

 

[Perry Babin]

Are you saying that the mute line is remaining at 12v and never drops?