Use a 700 degree F tip, stay off the pad and raise the tip to touch
the lead of the component only,  with the solder tip, instead of the pad to
avoid burning the board or lifting pads because it may be necessary to keep
touching the solder connection up to 9 seconds. Some boards are delicate and
some are not, it all depends.
        In one special case, it was necessary to heat up the board to 275
deg F by having the board up side down on a hot plate while it was being
soldered to get the minimum of 60 percent penetration. Good luck.
        Regards,
        Ramon

> -----Original Message-----
> From: Don_well [SMTP:[log in to unmask]]
> Sent: Monday, June 16, 2003 2:45 AM
> To:   [log in to unmask]
> Subject:      [TN] High heat sink board hand soldering
>
> Hi all
>
>     As we know hand soldering  PTH component is difficult on a tens-layer
> boards because of high heat sink.The solder volume filling level is always
> less than 50%. Could you please give me  any ideas to settle this
> problems.Below is only for referrence.
>
> 1 Preheat the board about 100 degrees before rework.
>
> 2 Design a enlarged pad before manufacture.
>
> 3 >=25% solder level is acceptable.
>
> Thanks for your advice.
>
> B.Regards
>
> Don
>
> Huawei Tech Ltd
>

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