Ubiquitiu 24 port POE. Help Identify Diode 3pin)

[gurj1979]

Hi again guys.
Ive got a Ubiquiti 24 port POE Switch which has failed to work. Fans turn on, but no lights.
I've ripped the board out, flipped it upside down and noticed a blown 3pin SMD Diode (at location D53). Marking is ESSP (as with all the other Diodes in the same row).

Anyone help me identify the model of this Diode ?

[SMDFlea]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

Hi again guys.
Ive got a Ubiquiti 24 port POE Switch which has failed to work. Fans turn on, but no lights.
I've ripped the board out, flipped it upside down and noticed a blown 3pin SMD Diode (at location D53). Marking is ESSP (as with all the other Diodes in the same row).

Anyone help me identify the model of this Diode ?

Looks like E5SP (five) to me .

https://cdn.badcaps-static.com/pdfs/...04da442b01.pdf
.

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

Looks like E5SP (five) to me .
.

You might be right. Terrible laser engraving by manufacturer. lol

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

I think I found it.

https://cdn.badcaps-static.com/pdfs/...04da442b01.pdf

[SMDFlea]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

I think I found it.

https://cdn.badcaps-static.com/pdfs/...04da442b01.pdf

I just added a picture and the same schematic at the same time as you posted

Last edited by SMDFlea; Today at 04:02 PM..
.

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

haha snap.
Thanks for helping.

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

The SoC is dead short to ground for 1v supply.
Must have been that ESD Diode that did it.
Ordered a new one (call it a dead one as always) from AliExpress. ETA 12th Sept.
Broadcom BCM53344A0KFSBLG

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

Chip arrived, put it in, worked for a while. Connected Ground strap and chip died again.
Found that something called Sidactor was shorted, causing voltage to go from 48v to Ground. Got another new CPU. New Sidactor ordered from RS Components. Will try it all out again tomorrow.

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

Update - So all that works fine now Happy days.
But I noticed Port 12 only works at 10/100 (Orange LED). All other ports work at 1000 (Green LED).

Any ideas ?

[stj]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

if the overvoltage protector failed (sidactor?)
then i would check all the transformer windings and the related caps and diodes - compare readings to a working one next to it

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

Looks like Port 12 is linked to LAN Transformer M-TEK G48209SNG.
So now I have to out where I can get this or equivalent from in UK. Perhaps RS Components again for quick and cheap price.
I'll update when I have some more new. But so far this is looking good.

[stj]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

dont just buy stuff, it could be a bad cap or diode or unfortunatly the chip it all feeds into

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

dont just buy stuff, it could be a bad cap or diode or unfortunatly the chip it all feeds into

6 pins (3 each on opposite ends) are giving zero ohms whereas others have high resistance.

I will check again for shorted caps but I didn't come across any today. Perhaps use my thermal cam.

[stj]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

that 0 ohms could be the transformer windings,
check against the diagram
http://en.mag-tek.com.cn/product/264...oductCateId=46

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

Correct for 3 pins in 1 side, but not on the opposite side. It turns into magnetic inside the transformer, then outputs to the opposite end. None of the other transformers are 0 ohms on opposite ends.
I'll check again for caps today in a couple of hours.

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

Update.
I've removed the The M-TEK Lan Tranaformer and one of the coils is burnt to smithereens.
See the pic. 2nd coil from left.

Now I can't buy this LAN Transformer anywhere in UK, not most of the world.

Can someone help me find a suitable replacement ?
It's 48 pins, 10/100/1000 POE, Single Port, 350uH.

From the datasheets, the left side has 2 pri coils, and right side has 1 sec coil. But most replacements on the market are Dual Ports with coils on opposite sides.
If I buy Dual Ports, would it affect the way the switch works ?

Thanks for all your help so far.

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

I've ordered this as it's the nearest thing I could find. Although it's Dual Ports instead of Single Port, I can't how it makes any difference. All the pins match up, the coils are in the exact same order as original, only the casing is larger by a couple of mm. Will try it later today.

https://uk.farnell.com/te-connectivi...-ddd7-00001003

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

Result. Works a treat. Port 12 now has Green light 1000mbps. Job is a goodun.
See pics for comparison of the 2 LAN Transformers.

[stj]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

nice.
lucky you only needed one, the extra width would envolve cutting the ends off the package.

[gurj1979]

Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

Very true. But I found that port 12 POE doesn't work neither. Works as non-POE. So back to the drawing board. Getting closer though.