Sundown SAZ3500D

[caraudioguy2100]

With a solder bridge between pins 2-3 the amp still goes into protection

 

[Perry Babin]

Confirm that you have no pulse of DC on the input of either large output filter inductor on startup (when it goes into protect).

 

[caraudioguy2100]

I get a pulse of About 80 volts on the input of the output filter inductor

 

[Perry Babin]

On both or just 1?

 

[caraudioguy2100]

Both

 

[Perry Babin]

They're directly connected.

Can you (relatively) easily desolder one terminal of one of the inductors?

 

[caraudioguy2100]

Yes I desoldered one of the terminals on 1 inductor

 

[Perry Babin]

At the point on the board where you desoldered the winding, do you see the 80v pulse?

Do you see it on the other inductor?

 

[caraudioguy2100]

Yes on the board where I desoldered the inductor I get a pulse of DC of 110 volts now and it’s also present on the other inductor

 

[Perry Babin]

Do you have a desk-lamp or something similar with a 110v incandescent (not LED, not CFL) bulb in it?

I want something to load the pulse to see if we can determine where it's coming from.

 

[caraudioguy2100]

Yes

 

[Perry Babin]

Connect one side of the plug to the speaker negative (likely directly connected to the main ground).

The other side will go to the points where you were checking for voltage.

Which point causes the light to light up?

 

[caraudioguy2100]

The outputs test good besides 1 bank

On the bank in question I get -98 volts on the gate and source and 110 volts on the drain

 

[Perry Babin]

Did you try the light?

 

[caraudioguy2100]

I’m getting the bulb to light up when I touch the tab of the 7812 regulator isn’t that suppose to be ground ?

I can also make it light up on the output leg of the 7812

And what are some areas you want me to check to see if I can get it to light up

 

[Perry Babin]

The 7812 regulator ground may be on the negative rail.

At this point, I just want to know which half is driving the pulse. Touch the free wire of the bulb to the point where you desoldered the inductor.

The second point would be the other inductor.

 

[caraudioguy2100]

I was touching the first spot where I unsoldered the inductor and it blew the outputs and blew the driver ic .

Once I replace these again I’ll get back to you

 

[Perry Babin]

That's odd. The 2-3 jumper shuts down the IC.

Double-check the gate resistors for the outputs.

 

[caraudioguy2100]

Back to this amp .

You were right about the gate resistors for the outputs .
I didn’t notice it before but someone put in the wrong value .

Also the 100k resistors were not the right value as someone replaced them with a much lower value .

Since the values were wrong could this have caused the voltage I was seeing on the inductor when powering up ?

 

[caraudioguy2100]

Never mind I answered my own question the amp blew the outputs again