Nee how Don,
The typical preheat sections are tunnel ovens that have a combination of IR
and convection heating.
With ENIG you are trying to solder to nickel which requires considerably more
heat [time and/or temperature] than soldering to copper--not only that, but
in many cases the solder joint is already formed because of HASL.
There are no files attached to your e-mail [IPC strips them off--you can send
them to me directly]--so I cannot comment. However, you may have 'Black Pad'
failures which show up first in SJs that see high temperatures such as would
occur with manual soldering.
I hope this helps.

Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL  32174  USA
Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com

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