Hi Technos,

I'm in big trouble with a backplane.

It's a 13.5"x19.5", 3.7mm thick. The connectors are disposed in parallel
lines, forming two columns a the two extremities. In the middle we have no
components. In between the connectors there are some TH caps and resistors.

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For a long time the soldering was OK, with small problems in the four
corners ( a couple of holes not 100% full).

For about a week or so, the solder joints of many caps or resistors present
cold solder. There are no significant cold solder problems with the
connectors, which present though a little less wetting (some of the fillets
are not what they used to be).

The question is: why do I get the cold solder and how can I get read of it?

We use :
- no-clean technology
- Multicore Sn63 solder
- Multicore X33 flux
- strong radiation preheating ( two top preheaters at 700F and two bottom at
750F); we spent a lot of time tweaking to avoid damaging the board
- two passes, one for fluxing only, no wave, the second one right after with
no fluxing, but with wave
- no chip wave (that's what I have, hehehe), just omega on our Electrovert
Econopak II

Any help would be greatly appreciated.

Thanks,      Ioan

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