Rockford Fosgate BD10001

[seankane]

Same scope settings 10 vol/div 5 us

First pic pin 6 of U5 second pic pin 6 of U8 this is what I see.

 

[Perry Babin]

The photos didn't load.

 

[seankane]

OOPS here they are!!!

 

[Perry Babin]

That looks OK also.

Confirm that you have a clean signal on pin 1 of U4.

I don't like replacing parts without having good reason but I'd suggest replacing U17 to see if it's the problem (assuming that U4 is clean).

 

[seankane]

What should the signal look like on pin 1 of U4?

The scope is triggering but there is not any wave from to speak of, should I try a different setting?

 

[Perry Babin]

That's going to be audio. If you drive a 100Hz sine wave into the amp, you should see a clean sine wave there.

 

[seankane]

I drove a 100HZ sine wave into the amp. The input at the RCA shield shows good wave form, and pin 7 on U4 shows good wave form and amplifies as volume is increased. Pin 1 of U4 hardly has a signal even at full volume it barely does anything. If I change scope settings I can get it to but its not clear makes a big haze over the screen of the scope but you can see the waveform.

Does this make sense to you, or did I explain it wrong?

 

[Perry Babin]

You'll have to set the timebase to about 2ms. Set the vertical amp to 5v/div.

Are you sure the sine wave is 100Hz?

 

[seankane]

You'll have to set the timebase to about 2ms. Set the vertical amp to 5v/div.

Are you sure the sine wave is 100Hz?

Those are the settings I am using. Yes the sine wave is the one you sent me in a link and I downloaded and burned to a disc. Its 100HZ for 300 seconds.

I have good signal on the input, and pin 7 of U4 but hardly anything happens on pin 1 of U4.

 

[Perry Babin]

Try changing the position of the 0/180° switch.

 

[seankane]

Switching it to 180 instead of 0 made a little difference. I can see a small wave now but nothing like the input or pin 7.

 

[seankane]

Ok got it moved the cross over switch to a different spot and got the signal, but doing that made the buzzing inside the amp 3 times as loud.

What is the buzzing from? Is it the sinewave in the transformer or is something trying to pull the DC off the speaker terminal?

 

[Perry Babin]

Try the other switches (subsonic?).

 

[Perry Babin]

Does it do it without the input signal?

 

[seankane]

I tried all the switches I turned the cross over to 250Hz and I get a good signal on pin1 of U4. The buzzing only happens when you turn up the volume. It does not do it at an idle with or without a signal. The louder you turn the volume the louder the buzzing. Coming from somewhere right by the speaker terminal.

 

[Perry Babin]

Does the amp produce clean audio now?

 

[seankane]

No same issue. Wierd thing is though when you switch the phase 180/0 or the sub sonic both switches make the amp squeel through the speaker.

 

[seankane]

Maybe I should replace U17 and U4 and the 2 switches?

 

[Perry Babin]

Use your meter to determine if the switches have too much resistance in either position. If they're OK, change U4 if you can't get a clean signal.

After you get a clean signal on pin 1 of U4, check for clean audio. If it's still badly distorted, replace U17.

I'm done for tonight. I'll check back when I get some free time tomorrow.

 

[seankane]

Changed both switches with new ones and replaced U4 with a new one.

Same problem with amp, does not produce clean audio and switching the switches makes the amp squeel through the speaker.

Amp still has a loud buzzing noise with signal to it at high volume.

I ordered 10 LM6171 today from allied, I can try changing that but I dont know what else to do. U17 is my next target when I get them in the mail.

Unless you can think of something else I could check in the mean time, but everything you had me check so far looked good, so I am not sure where to go next????