Hi all,

Had an odd problem today.

We have built many of these assemblies with tin/lead solder but just now switched to lead free solder (higher temperature).

The "Dissopad" contacting the PCB (at a via) liquefied, spread and charred. The residue is very difficult to remove, especially a concern since it is under components and could be "conductive". (pix available on request)

We tried cleaning this with isopropyl alcohol and it didn't seem to dissolve the charred residue at all.

I soaked one PCB in 140F DI water for 30 min. and re-cleaned in the aqueous cleaner. It did seem to remove the heavier residue, but there remains a film and smaller clumps on the board surface.

Any suggestions would be appreciated!


Ed Popielarski
Engineering Manager

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