Topic: ADI-2 DAC fs short circuit / Kurzschluss

Hello friends . With my converter, the protective diode that sits between plus and minus on the printed circuit board is broken right after the mains input socket. Anyone know the name or have a schematic?

Hallo Freunde . Dei meinem Wandler ist gleich nach der Netzeingangsbuchse die Schutzdiode die zwischen plus und minus sitzt auf der Leiterplatte kaputt. Kennt jemand die Bezeichnung oder hat einen Schaltplan?


Ich Danke Euch .Lg

Re: ADI-2 DAC fs short circuit / Kurzschluss

Das Bauteil gleich hinter der Buchse ist ein Wiederstand, 1,5 Ohm:

https://i.ibb.co/JvMPPNC/F650-E89-E-DD23-4-E65-9922-A1-F5421-EB675.jpg

Re: ADI-2 DAC fs short circuit / Kurzschluss

from online high res ADI-2 DAC PCB image:

https://i.ibb.co/jDtwGzd/Screen-Shot-2022-05-22-at-1-00-24.png

Re: ADI-2 DAC fs short circuit / Kurzschluss

Schon mal vielen Dank für eure Hilfe . Auf dem Bild von "ning" sieht man sie gut mit dem Aufdruck BEJ 8AY was aber kein normaler SMD Code ist  . Zenerdiode oder  shottky oder ganz normale Schutzdiode  ??? Diese Bezeichnung bräuchte ich...

5 (edited by KaiS 2022-05-21 18:20:04)

Re: ADI-2 DAC fs short circuit / Kurzschluss

Wenn’s ‘ne Schutzdiode ist, sowas hier:

https://www.digikey.de/en/products/deta … AY/5210277

https://www.st.com/content/ccc/resource … 035136.pdf

https://de.wikipedia.org/wiki/Suppressordiode

Wenn Du die gebrutzelt hast, hast Du aber ordentlich verpolte Power drauf gegeben.

6 (edited by ning 2022-05-21 19:46:16)

Re: ADI-2 DAC fs short circuit / Kurzschluss

Don't know. smd code database points it to the P4SMA Series TVS Diodes.

recent Pro FS R circuit board has replaced it with a PTC fuse that looks like this one https://www.belfuse.com/product-detail/ … cj-series.

https://i.ibb.co/QN2NCYy/Screen-Shot-2022-05-22-at-3-23-34.png

(scaled from a photo of my previous broken unit a year ago. I no longer have a chance to get a clearer picture.)

They are not the same part but a reasonable guess is they serve exactly the same purpose.

EDIT: based on available datasheet it should be this one: 0ZCG0160BF2C
https://www.belfuse.com/resources/datas … series.pdf

7 (edited by KaiS 2022-05-21 21:17:10)

Re: ADI-2 DAC fs short circuit / Kurzschluss

Seems there are quite some variations at this point.

BTW:
The 1.5 Ohm resistor or the coil that replaces it in the other variants (marked •B) might be broken too, if it’s in front of the diode and in series with the PSU.
As far as I can see the circuit traces it is.

8 (edited by ning 2022-05-22 03:53:13)

Re: ADI-2 DAC fs short circuit / Kurzschluss

https://i.ibb.co/yNbr7Y7/Screen-Shot-2022-05-22-at-1-00-34.png

There are variations. here's another online PCB shot with another diode like component, but not marked with BEJ.

RME may replace the components when there're availability issues.
In this case, the replaced component will have the same purposes and meet the required performance in this circuit.
I would just replace it with 0ZCG0160BF2C if I cannot identify the original diode.
should have similar size (albeit not the same size, it should fit on existing solder pads).

9 (edited by KaiS 2022-05-22 05:50:41)

Re: ADI-2 DAC fs short circuit / Kurzschluss

ning wrote:

There are variations. here's another online PCB shot with another diode like component, but not marked with BEJ.
... I would just replace it with 0ZCG0160BF2C if I cannot identify the original diode.

With all this variants, you have to find out if the part is in series (Fuse) or parallel (Protection Diode) to the PSU voltage.

Reversing this would not work, a fuse parallel to 12 V would just blow, a protection diode in series would block the supply voltage.

My guess is, the thermal fuse is RME’s latest iteration on their quest to optimize the circuit, as it’s the most user friendly, it resets itself.

But that’s a different board layout too, and probably thermally critical.


Now that even Apple has to supply spare parts, maybe RME can send the fitting piece smile

Re: ADI-2 DAC fs short circuit / Kurzschluss

that's right. I haven't look into the circuit and see how it works.

Re: ADI-2 DAC fs short circuit / Kurzschluss

That's how it looks with my (early) Pro FS-R:
https://abload.de/img/adi-2profsrdcinput9gjmd.jpg
We can spot:
DC-Jack --> 2x RF Shunt Cap to GND --> 1.5uH Series EMI coil (+ another cap to GND, supposedly) --> Series PTC --> Shunt Reverse Protection Diode (might also double up as Unipolar Transient Suppressor Zener), or vice versa. At this junction we also have a P-Channel MOSFET as a high-side switch which cuts off power to the various subsequent DC/DC-converters in Standby Mode.

The Polarity Protection is essential (the PMOS switch won't protect against reverse DC since it just a shortable diode anyway ;-) And the added PTC prevents the coil and the diode (and the supply itself) from overheating by limiting the reverse current to approx. 1W/12V=80mA continuous.


@ranger4711,
If your device has suffered from a sustained reverse polarity DC supply incident, I would also think that the series coil blew up (disrupting any power input from there on) and the diode itself might still be working (but should be replaced anyway) unless it melted as well, often producing a dead short. Therefore, I'd check for conductivity of the coil and for shorted diode first.

I'd contact RME (or Matthias) directly for (compatible or original) part numbers.

12

Re: ADI-2 DAC fs short circuit / Kurzschluss

The diode is a P4SMA18CA, a bi-directional TVS diode of 18 V. So it's not about polarity, but too high voltage (wrong power supply) connected to the DAC. Note the 1R5 is not a resistor but  a coil with 1.5 µH.

Posts of the Pro are not relevant here, the DAC had a slightly different protection circuit.

Regards
Matthias Carstens
RME

Re: ADI-2 DAC fs short circuit / Kurzschluss

Thanks, according to ECADATA it would be a P4Sma18A TVS diode by TSC. Since it has no directional marking I think it could be a bidirectional 18V surge diode. It doesn't help against polarity reversal, but it's the most obvious.

@KSTR
Where can I find   Matthias?

Re: ADI-2 DAC fs short circuit / Kurzschluss

@MC . Sorry our articles overlapped. Thanks for the help, now I know for sure :-)

Re: ADI-2 DAC fs short circuit / Kurzschluss

Danke Euch , Der ADI läuft. Nur noch eine Frage ...das Display schaltet nach ein paar sekunden aus wenn man keine Taste benutzt , ist das normal und kann man die Zeit einstellen ???

Re: ADI-2 DAC fs short circuit / Kurzschluss

Der "Auto dark" modus ist aktiviert.
Im Setup deaktivieren, die Zeit lässt sich nicht einstellen.