Edimax ES-3208P repair (cannot identify smd based on marking code)

[ro0ter]

Hello all,

I have received an Edimax 8-port switch from my sister that most certainly fed it 12v on its the 5v input... (I cannot guarantee that, but based on the damage I suppose that happened.. or maybe the PSU failed - I got no PSU).

The problem is quite straight-forward, there is a smd in a very strange package which is burnt. I took a picture which shows its marking code(s) very well then I touched it with a small screwdriver and indeed it scraped away, the plastics boiled (no soldering residue).

I have attached a picture to this post. The marking code on the piece is "3022" / "A10B". I couldn`t find anything regarding this piece (only some MOC3022.. but lol, there`s no AC... and a 3-pin TV diode, but to me it seems rather more a dc buck controller... not sure what voltage it outputs, as there is another SOT-89 "772" / "0A01" regulator closer to the IP178D, which may supply the 3v3... I would test whether the brains of this device are also fried, but since I don`t know the voltage it should output.. no chance... I will desolder it later on today and see if it has any marking code on its belly as well.

Anyway, this SMD piece is quite interesting, as you can see: the package seems to be SOT-89 but with extra 2 pins on both sides of the thicker pin... what in the world should that be?

Any help is highly appreciated, thank you very much!



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NOTE: Allover the circuit there are 0R 1206 resistors used as inductors... (at least the board states Lx), none of which are toasted.

The resistor near the top-right capacitor in the photo is 010 (that is 1 ohm) and it seems just fine (didn`t measure it yet).

There is a huge inductor (33uh - the one to the left) connected to pins 1 and 3, a sk228 (5831a zener?) connected between pins 2 and 1.

+ input enters the pin 5 (last pin, e.g. pin 6, but since pin 2 is same as pin 5, I did not count it).

Any other questions there might be, please do ask.

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SOT-89-5 is the package, as I have noticed on Farnel`s website (not sure if found product is relevant here, yet it is a led driver with switching frequency etc - **broken link removed**)

 

[d123]

Hi,

Based on your SOT-89-5 package description and the marking A10B, came up with: Good Transient Response Low Voltage 500mA LDO The code marking list is on page 20 of the datasheet, "RP111H Series Mark Specification Table (SOT-89-5)". Could (or may not) be the right part..., the orientation of the markings in the drawing is perpendicular to those of your part in the photo..., ..., ...hope it helps.

 

[ro0ter]

Hi,

Based on your SOT-89-5 package description and the marking A10B, came up with: Good Transient Response Low Voltage 500mA LDO The code marking list is on page 20 of the datasheet, "RP111H Series Mark Specification Table (SOT-89-5)". Could (or may not) be the right part..., the orientation of the markings in the drawing is perpendicular to those of your part in the photo..., ..., ...hope it helps.

Indeed, that might just be the order. How did you managed to find this part based on the package and the marking code? I know Google is everyone's best friend, but I did not find it over 4+ hours of searches....

Anyway, thank you very much, this thread is now solved! I will keep you updated with the progress, should I be able to find and order this part.

Regards!

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Yet, after checking the circuit again it must be that the component should be a switching regulator - mind the inductor and the diode.... It most certainly cannot be a 1.0v LDO, but so far d123's guess is the best. I will keep looking for the right component. The back of the component has no markings (obvious)..

 

[betwixt]

I would make a guess at it being an NJW4132. It's the right shape, a switching regulator and seems to have the pins wired appropriately. The only potential problem is it should have survived 12V at it's input, unless it was fed 12V AC of course!

Brian.

 

[ro0ter]

Thank you betwixt for your suggestion. I have checked the datasheet but unfortunately its wiring (namely the inductor and rectifier diode) goes between the wrong pins... I guess I will abort fixing this switch as a new one should be very cheap and it already costed me too much time.

The NJW4132 has the pinout 1 = SW / GND / IN- / EN_SYNC / V+ = 5. The inductor is pictured between the V+ and SW pins (5 and 1) and the diode is from inductor to vout.

On the Edimax boart the inductor sits between pins 1 and output and the diode is from GND to pin 1... much like a buck converter... I really can`t tell for sure the schematic unless I desolder capacitors/inductors... I guess I`ll do it just for the curiosity.

Thank you all for your time and efforts!