SoundStream BXA1-5000D audio problem

[Perry Babin]

Try connecting a dummy load across the speaker terminals. Does that make a difference?

 

[Formas]

I do not have a 8 or 4ohms 10 or 15watts resistor at hand, can I use a speaker for that test?

 

[Perry Babin]

With no output FETs in the circuit, you shouldn't need a high-power load. If you use a speaker, use a woofer, not a fragile speaker. The load can't have a capacitor in series with it.

Power up and confirm that there is nothing more than a tiny fraction of a volt across it.

2 ohm current limiting resistors work well for this.

If this doesn't work, I need to see the components driving the driver board.

 

[Formas]

That didn’t work still a good low side drive nothing on the high side.

 

[Perry Babin]

But... the low-side didn't disappear with the load, correct?

Confirm that you have 9v across the high-side terminals of the driver IC.

 

[Formas]

The low side didn’t disappear even with load.
If the high side terminal is where the battery test was done, I’m not getting any volts across those terminals.

 

[Perry Babin]

The capacitor across those terminals could be shorted.

The IC could also be damaged. These aren't as sensitive to heat as other ICs but they can be damaged when installing them.

If you find the short, the battery is likely drained.

 

[Formas]

I did not leave the battery hooked up continuously to the circuit, and when I connected it I parallel my probes and the voltage was stable, I’m not getting a short across the cap so then the IC may be faulty, I’ll replace the IC and report back.

 

[Perry Babin]

That sounds like a bad connection.

 

[Formas]

When testing voltages, what is the reference point for the negative probe on the driver card as most points for example the Vdd and Vss gives me 77volts also the marked 5v when referenced to ground gives me same 77v?

 

[Perry Babin]

For the high-side, you need to measure across Vb and Vs on the IC.

For most of the other other terminals, the negative rail is the reference.

 

[Formas]

So pin 6 & 7 should get 9v from the 12+ which is present when I measure across the 12v pin and the driver card Vcc.
If I remove the IC or lift those two pins should I see the missing volts on the respective pads?
I’ve check and double check there’s no broken solder joint and all the vias are connected.

 

[Formas]

I’m thinking a bad chip as I’m not seeing any bad parts surrounding the high side supply defective. It’s just a simple arrangement two diodes, a cap and a 10ohm resistor to pin 6 and 7, which the 12volt is not missing but no volts on those pins.
Is it practical to lift the IC legs and see if it’s the ic which is clamping down the voltages?

 

[Perry Babin]

The only time that the high-side gets 12v from the 12v regulator is when the low side FETs conduct.

Correct where I'm wrong.

You have 9v across the capacitor that the battery is connected to.

You have no voltage across the VS and VB terminals.

 

[Formas]

The pin 1 on the driver card goes to a 12v source that I think would constantly power the Vb and Vs pins on the driver chip directly. As I said that circuitry around those pins are just a zener diode a cap a fast switching diode and a 10ohms resistor, I think 9volts should be present as long as the 12volt is on pin 1 of the card.
When I test there was 12v present put the 9v wasn’t present on the 6 and 7 pin of the ic.

 

[Perry Babin]

Do you read 12v on pin 1 using either the primary or secondary ground as the reference?

 

[Formas]

No, I get 68v when use those ground as reference, but when use the -Vcc I get 12v.
Bear in mind the card isn’t in the circuit at that time of measure, I’ve removed it to replace the IR2010S chip.