Soundstream lil wonder 5.1000 power-on bump

[picco76]

Remove the bridge.

What's the DC voltage across terminals 1 and 2 before the end of the mute delay?

When power on, start from 0.09v and go to 1.16v (muting off)

 

[Perry Babin]

Parallel a capacitor (about 100uF) across terminals 1 and 2. Does that stop the bad channels from popping?

 

[picco76]

Remove the bridge.

What's the DC voltage across terminals 1 and 2 before the end of the mute delay?

Parallel a capacitor (about 100uF) across terminals 1 and 2. Does that stop the bad channels from popping?

I have checked the voltage across pin 1-2 of the optocoupler better, i have -0.9V when is power off, when power on start up to 1.16V.
I have tryed with 100uf but no result, it's the same

 

[Perry Babin]

C45 may be part of the delay on.

Is the voltage across this cap (just before applying remote voltage) the same when the amp pops and when it powers up quietly?

 

[picco76]

C45 may be part of the delay on.

Is the voltage across this cap (just before applying remote voltage) the same when the amp pops and when it powers up quietly?

Yes, it's the same

 

[Perry Babin]

What was the voltage?

 

[picco76]

What was the voltage?

14v (power on) to -0.2v (power off)

 

[picco76]

I have tried with 10k resistor on optocoupler pin 1-2, the voltage, when i leave remote in, go to 0v fastly, but the pop is still present..

 

[Perry Babin]

Does Q9 drive the opto-coupler via the 1k 1/2w resistor?

If so, pull it and see if the pop is gone.

 

[picco76]

Does Q9 drive the opto-coupler via the 1k 1/2w resistor?

If so, pull it and see if the pop is gone.

Yes, q9 is optocoupler driver. Without Q9 i have the same pop

 

[Perry Babin]

Did you try lifting terminals 1 and 2 to disable the opto-coupler or did you only try shorting them?

If you rub the tip of your scope (on DC coupling, 1v/div, 2ms/div) probe around in the area of the optocoupler (both sides of the board), does the trace ever deflect from the reference.

 

[picco76]

Did you try lifting terminals 1 and 2 to disable the opto-coupler or did you only try shorting them?

If you rub the tip of your scope (on DC coupling, 1v/div, 2ms/div) probe around in the area of the optocoupler (both sides of the board), does the trace ever deflect from the reference.

I have only shorted pin 1-2

 

[Perry Babin]

Did your scope have any deflection when checking for leakage as suggested?

 

[picco76]

Did your scope have any deflection when checking for leakage as suggested?

No deflection

 

[Perry Babin]

Confirm that you had absolutely no pop on any channel, no matter what with terminals 1 and 2 shorted?

Lift 1 and 2 and retest for noise.

 

[picco76]

Confirm that you had absolutely no pop on any channel, no matter what with terminals 1 and 2 shorted?

Lift 1 and 2 and retest for noise.

Optocoupler pin 1-2 shorted= no pop
Optocoupler pin 1-2 lifted= pop present

 

[Perry Babin]

That makes no sense, to me. Do you have another optocoupler that you could install?

 

[picco76]

That makes no sense, to me. Do you have another optocoupler that you could install?

Yes i think, i must check datasheet, let you know

 

[picco76]

That makes no sense, to me. Do you have another optocoupler that you could install?

I have tried with another optocoupler, no difference

 

[Perry Babin]

Solder the lifted terminals together. Does that eliminate the pop?