LPC Link 2 - Ferrite Bead Burned (L3)

[romanleonov]

Hi! 

I have two two boards LPC Link 2 with burned ferrite bead. 

First of them burned some about two years ago. Then I thought that it was just a defect of this board only.

Small ferrite bead (L3) was destroyed. 

But now, when my second board burned last night I started to think that it could be a product line defect. 

Does anyone come across the same problem? 

Solution? Replace the ferrite bead?)

Here are some photo with issue.

[BlackNight]

They look badly burned! I'm using the LPC-Link2 alot too, but never saw this (yet?).

The L3 is on the +5V line. I'm wondering if you had some short ciruit somewhere.

Or that the host somehow injected a voltage too high (but the diodes should protect from that).

I would try to replace the L3, but it could be that other parts have been damaged with over-current too.

I hope this helps,

Erich

[romanleonov]

I'd replaced L3 part on the both boards and they began to work well. 

Thus, only L3 was destoryed. But on the one board copper layer was destroyed also so I had to make solder connection)

[romanleonov]

Hi Erich, 

Thank You for your reply.

Yes I had founded the schematic and already found the place where I can buy BLM15AG121SN1D part. 

Also I recognized that there is some similar problem with L3 was here: Anyone using the LPC-Link 2 with MCB1857 KEIL development board?

But I hadn't have any other power consumer connected to the board because I use different power source for LPC Link2 and a target board. 

So, just wonder)

[BlackNight]

I'm not sure what you mean with 'use diffent power source': I definitely recommend *not* to have the JP2 in place if your board is able to draw more than say 30 mA or so. The article you have found seems to indicate that possibly JP2 could have caused the problem too.

[BlackNight]

Just another thought: On the picture I see you have JP2 installed. I rarely use that (I avoid that if not in a real need). Maybe your device was drawing too much current over an extended period of time?

The BLM15AG121SN1D is rated for 500 mA, but if this is used for too long and with some part variations, this could have burned it.

I hope this helps,

Erich

[romanleonov]

Yes, that is correct. My JP2 is intalled. 

But I do not use this connector on the other side, so it is just floated. 

I want to remove it on the third board and see how it will goes..

And I'll try to fix these two boards then)