Steve,
Get someone to "fess up" that they spilled something on it!
D. A. Douthit
"" wrote:
> '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
> respond to
> "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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