Dynaudio focus 400xd schematic & help please

[zen]

Hi all

With mains applied , i can hear 1 relay click , then a second or so later a second click .

3.3 volt supplies stable .

The 36 volts supply rises , then falls away , after second relay click .

Cannot find any faulty electrolytic capacitors .

Also spent ages removing that glue manufacturers like to use , that becomes hard & corrosive .

No obvious short circuit reading .

[zen]

Re: Dynaudio focus 400xd schematic & help please

Strange that 2 speakers have failed , with exactly same symptoms .

Must be a common cause .

These speakers even have a USB port for upgrading .

[Khron]

Re: Dynaudio focus 400xd schematic & help please

That's not a whole lot to go on, though.

I see a TNY___ chip there, with a small transformer next to it; is that some "stand-by" supply? Do these speakers have some sort of idle-timeout or auto-off/on features?

But all(?) the electrolytics seem to be Ltec. I believe only Delta, by whatever unholy voodoo magic they do, manage to make them last as long(?) as Japanese capacitors, in their own power supplies.

"That glue manufacturers like to use"? You mean the dark-cheese / tan coloured one? Was any of that used in here? I'd find it odd, since they used that white silicone / RTV on the top of the power supply...

[zen]

Re: Dynaudio focus 400xd schematic & help please

Hello Khron .

PSU seems good & yes standby supply present.The TNY chip seems to be for that part of circuitry .


The glue i refer to starts off a white colour i suspect , then due to heat , turns a crispy brown corrosive substance .

Very common on many active speakers i have worked on . Really surprised all the electrolytic capacitors check out good .

[zen]

Re: Dynaudio focus 400xd schematic & help please

Finally customer dropped off remote for the speakers .

Turns out they were both in standby .

Remote had battery leakage on contacts .

Cleaned up & tested .