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May 2001

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Subject:
From:
"<Peter George Duncan>" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Tue, 22 May 2001 08:33:27 +0800
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'Morning, Steve,

Not a pretty sight! And none of the other boards are showing ANY sign of a
similar attack? Where was the victim placed in the chamber - middle, near
the door, near the back, one side or the other? Near inlets or outlets?
Where was it situated in relation to the other boards?

Was this board cleaned in the same batch as the others? Was it cleaned? Did
some mishap befall it afterwards that someone's keeping Mum about?

I can honestly say that I have never seen a case like this at all. For the
damage to have spread so far, I would have thought there would have been
some obvious sign of contamination before the board went into the chamber.
If it's flux, it would have to be pretty active like an RA, but does anyone
still use RA on boards?

If you reckon the board was clean, there are few other places it could have
come from but the board itself - or sabotage! This is no real help but a
couple of cents worth that might trigger some better responses. The chamber
itself is OK, is it? Nothing deposited inside that could give off corrosive
gasses?

Are you sending the body to forensics for autopsy? See what residues now
remain on the surface.

Good luck.

Pete Duncan




                    "Stephen R.
                    Gregory"             To:     [log in to unmask]
                    <SteveZeva@AO        cc:     (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group)
                    L.COM>               Subject:     [TN] Assembly "ate-up" after temp cycling...
                    Sent by:
                    TechNet
                    <[log in to unmask]
                    ORG>


                    05/21/01
                    11:22 PM
                    Please
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                    "TechNet
                    E-Mail
                    Forum.";
                    Please
                    respond to
                    SteveZeva






Hi ya'll!

Well, I survived all the tornados we had yesterday...almost a dozen of them

all around my area!

Came in this morning and one of the supervisors showed me a board that came

out of a temp cycling oven after being in there for 32-hours...the temp
cycles are from 0-70 degrees C., 14 cycles over 32-hours. There were around

15 other boards in the oven,
but one came out looking like there was acid spilled on the backside, mask
was off all over the back, solder joints had been eaten away, as well as
pads!! It was the only board that had this...go to:
http://stevezeva.homestead.com/index.html

I've been asked what may have caused this...it looks to me like there may
have been some flux left on the board. Some say that it may have happened
from condensation that may have occured during the temp cycle, I say if
that
was the case, all the boards would like this. Something else had to be
involved for the copper and solder to be eaten away like this...what do you

guys think?

-Steve Gregory-

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