"John Larkin" wrote in message
...
This is the Lantronix Xport module.


http://www.lantronix.com/device-netw...vers/xport.htm
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This particuler unit randomly, a couple of times a week maybe, draws a
lot of power and gets very hot, 80C or so, and still works, but
flakily. So we decided to rip it open and see what's inside.

I love those LEDs.

At least one looks to be bi - color as it looks like there are two bond
wires and two LED dies in it.

There seems to be significant manual assembly needed for these, as it would
be hard for a robot /selective solder to solder many of the through hole
components (LEDs, inline header, ground wire, connector going to the outside
for your PCB, RJ45 pins (they are SMT on both sides of the board), the
transformer wires (these may be wave or selective soldered)). The manually
assembled parts look to have significant weird looking flux residue around
them, at least on the blue board.

Weird ground wire (I assume) going to the rear case.

I am quite surprised they used a 1.6 mm thick PCB, and one close to it. I
suppose they have the room (there is surprisingly a lot of room left over).
The simple top PCB is at least a 4 layer PCB.

It's weird they used a custom set of pulse transformers and potted them to
the PCB. They must have had problems finding one small enough, but then
again the ones in PCMCIA cards were quite small.

I'm surprised the Atmel memory IC is a BGA - all the ones I've currently
used and seen were CASON 8 or oversized body SO8's

There are a bunch of 0402's. The pads width and overall length looks good,
but the gap between the two pads looks a little large - possible tombstone
or worse, drawbridge problems, but without having the actual dimensions or
looking at the board in more detail, it's hard to say.

There is no evidence of something getting hot - usually the PCB will darken
in high heat areas, and if really hot, the solder joints will melt a bit,
giving a cold solder / wrinkly look to them


The two chips are a Lantronix thing and an Atmel serial flash. So
there must be a heap of ram inside the Lantronix chip, enough for the
tcp/ip stack and the jvm and all that.

I scaled the pic res down, as the original files were huge.

John