6 pin SMD ID HK E110 Sub

[Audiorepair]

Hi,
this is in an SMPS controller circuit, nearby is a TL072 and 555 timer.

Blown device seems to be marked "47S"
Nearby are similar packages marked "47P" and "57S", so may be complementary/different ratings?

Couldn't find anything in code search that appeared to suggest anything.


Cheers for any info if you have any suggestions.

[fzabkar]

Q207 suggests a transistor, but I can't think of any application where one would connect a capacitor between two pins of a MOSFET or BJT. :-?

[inse]

Dual Transistor, maybe?

[elecdonia]

Issues like this beg for finding another identical PC board which is in working condition to compare with. Sometimes I like to put 5 identical units on my workbench and compare them to each other. Even if some are not operational to begin with, it often turns out that that they don’t all have exactly the same fault.

[Audiorepair]

Q207 suggests a transistor, but I can't think of any application where one would connect a capacitor between two pins of a MOSFET or BJT. :-?

if you look at the 3rd photo, pins 5 & 6 are shorted, but not on the other examples.

That's a bit of a head scratcher.
(Not a good photo, but I could get a better one, though I assure you this is intentional)

[fzabkar]

Could we see the whole PCB?

[Audiorepair]

Could we see the whole PCB?

Yes I'll do that tomorrow.
The annoying thing is that I at first found a 555 timer with a hole blown in it.  The SMPS wouldn't get out of idle.

After replacing the 555, it worked!

Well, for 5 minutes anyway, then smoke came out, presumably from this 6 pin thing.
The replacement 555 looks a bit like it may have got hot too, dunno, will try to show that too.

Couldn't find schematics, it's an HK E110 Sub.

[Niklas]

47S in a SOT363 package could be a dual NPN from Panjit. 47P is a NPN+PNP and 57S is dual PNP.
https://eu.mouser.com/datasheet/2/1057/BC847BS-AU-1869637.pdf
https://eu.mouser.com/datasheet/2/1057/BC857BS-1869977.pdf
https://eu.mouser.com/datasheet/2/1057/BC847BPN-1869567.pdf

[golden_labels]

Could it be something from BAS40 series in a 6-pin SOT package? NXP, Infineon, OnSemi, Diotec, Diodes Incorporated all have similar families of Schottky diodes in various configurations and SOT packages. None I found matches exactly, but there might be other manufacturers.

[Audiorepair]

47S in a SOT363 package could be a dual NPN from Panjit. 47P is a NPN+PNP and 57S is dual PNP.
https://eu.mouser.com/datasheet/2/1057/BC847BS-AU-1869637.pdf
https://eu.mouser.com/datasheet/2/1057/BC857BS-1869977.pdf
https://eu.mouser.com/datasheet/2/1057/BC847BPN-1869567.pdf

That has to be it I think.

Thanks Niklas.

[Audiorepair]

Photos for Frank.

Contoller IC is IRS20124S


555 Timer above burnt transistor pair, TL072 below.

[Vicus]

Hi, who Is U200? I don't think that Q207 Is related ti the smps. Either with the IRS20124S. It could be that it is shorted and this prevent the smps to power up because it goes in to a over current condition.

[Audiorepair]

Hi, who Is U200? I don't think that Q207 Is related ti the smps. Either with the IRS20124S. It could be that it is shorted and this prevent the smps to power up because it goes in to a over current condition.

U200 is TL072.  The one above it is a 555 timer, so it looks like this is the startup/shutdown circuit.

The 555 timer was blown up.  I replaced it and the unit worked for a few minutes before burning the transistor pair.
Looks like the 555 timer also burnt again.

[Vicus]

Startup shutdown of what? Is the psu in a separate board?

[Audiorepair]

The HK E110 Sub is now fixed.

Turned out Q3 next to the 555 timer was also faulty.
This was marked 6C which I took to be a BC817.

So after replacement of 555 (again), Q3, TL072, and the BC847BS dual transistor that Niklas identified, all is now good.

The was some burning of the PCB and a lifted pad below the burnt dual transistor, but it's survivable.


Thanks to all.