Hi Linda!

While discoloration in itself is not a defect, I would be a little worried about these seven boards. Especially since the rest of the lot are not discolored like this: 


 http://stevezeva.homestead.com/PCB_Discoloration1.jpg

 

I don't see any delamination in the photos, but it sure looks like the boards got pretty toasty. I wonder if it was because the boards were sitting over a preheater or hot plate too long. From the looks of the components on the board, most of it was probably hand soldered (those PTH caps converted to SMT couldn't have taken reflow), and I imagine that the solid plane on on the backside of the board was a real heatsink. Preheating the board would have helped with soldering the PEM nuts for sure, but maybe the preheater was set too high. I know a Hakko IR preheater can smoke a board if you're not careful (not that I've ever done that, but I know a friend of a friend who did. Hehehehe).

 

Anyways, those seven boards saw more heat than the rest of them did based on the appearance in the photos. I don't think I'd buy off on them...

 

Steve

 

 

 

From: Linda Langley [mailto:[log in to unmask]] 
Sent: Thursday, July 29, 2010 1:42 PM
To: Steve Gregory
Subject: FW: PCB Discoloration

 

Hi Steve,

 

Here I go again asking for help from my experts! Can you please post these pictures? So I don’t have to bother the whole forum, would you know the name of the board guru that could answer my questions?

 

I am not sure if the discoloration is a defect, is this a form of delaminating? Why would only seven boards turn this color? They are all from the same lot.

 

Any information will be greatly appreciated.

 


Linda Langley CIT

Training Specialist

Jabil Circuit

248-292-6176

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