I'm thinking most of the above -- looks like creep from the plated holes
along the copper excited by the salt-air and the high current density.
Looks like FR-4 glass/epoxy to me.  I saw one instance where this had
jumped from the plane area to an adjacent conductor -- may be a fly in
the ointment...Ian

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Lazzara
Sent: Monday, December 04, 2006 12:13 PM
To: [log in to unmask]
Subject: Re: [TN] water water everywhere!

Brian,

Looks funny to me, too, but not due to it being a few holes.

First observation: There's apparent solder mask lifting/blistering. I
expect
to see uniform solder mask even when the substrate exhibits
delamination,
but these views show an effect appearing more like solder mask
blistering than
ply separation.

Second observation: I see solder mask separating from a trace.

Initial thoughts: This is a failure of the solder mask. The mask wasn't
uniformly cured (or there was inadequate surface preparation prior to
masking --
or both).

Q1: Is there an available edge-view of the PCB? The closer/the  better.

Q2: Has anyone performed IPC solder mask testing for peel strength  or
solvent resistivity?

Q3: Has anyone cracked open a box that hasn't gone into the field to se
if
the condition is pre-existing?


ROBERT LAZZARA
VP, Business Development
T: (800) 560-9457
F:  (800) 878-5566



____________________________________

In a message dated 12/4/2006 11:30:34 A.M. Eastern Standard Time,
[log in to unmask] writes:


The  following files show the two sides of a PCB in a professional
weather  station. This shows four dark areas which the manufacturer has
ascribed to  water penetration. These are centred on a hole. The whole
thing seems funny  to me, as it has happened on only a few of the holes.
I understand that it  was housed in a water-tight case, not very far
from
the Pacific coast. I  was not able to ascertain the laminate type, but
it
would not surpise me if  it were paper based (FR3?).

Has anyone seen anything like  this?



____________________________________



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