Tinning on old PCBs

From: jpero_at_sympatico.ca <(jpero_at_sympatico.ca)>
Date: Thu Dec 20 14:25:15 2001

> From: "Louis Schulman" <louiss_at_gate.net>
> To: "classiccmp_at_classiccmp.org" <classiccmp_at_classiccmp.org>
> Date: Thu, 20 Dec 2001 19:59:28 -0500 (EST)
> Subject: Re: Tinning on old PCBs
> Reply-to: classiccmp_at_classiccmp.org

> Yes, this is the actual lead/tin that is peeling off. There is no coating on this PCB, just the bare tinned traces
> on a bare board. I will admit, this is quite unusual, since the solder must have flowed out to tin the traces in
> the first place, yet it did not bond properly.

I seen this once on Seagate HD ST1201A. Many SMD simply
popped off easily leaving bare copper where solder "bonded" to it.
Phyically when intact, looked good but that layer between copper and
solder is bad even everything looked "wetted" properly. Ditto to
many component leads (also on thru hole) even it was "soldered"
properly at factory.

Everybody else here's the Qs:
What is this failure called?

What causes this failure?

Cheers,

Wizard

>
> Louis
 
Received on Thu Dec 20 2001 - 14:25:15 GMT