Solder Problems (PDP-8/m related)

From: Joe <rigdonj_at_intellistar.net>
Date: Fri Dec 3 23:03:14 1999

At 12:59 AM 12/4/99 +0000, Tony wrote:
>> >Perhaps it was this list, but I have just read about solder removal alloy.
>> >Its a solder looking stuff used to remove complex multipin chips. You melt
>> >it onto the existing solder and it forms an alloy with a VERY low melting
>> >point so the chip can be removed with much less heat, ie wave a heat gun
>> >and it drops off.
>>
>> That's an interesting idea. But I certain that you'd have to heat the
>> joint to the melting pont of the old solder before this stuff would alloy
>
>Yes, sure you do.
>
>But the point is you can heat the pins of a PQFP (or whatever) _one at a
>time_ and melt some of this alloy into the solder, thus making the
>solder-alloy mix melt at a much lower temperature. Then, after you've
>treated all the pins you can warm the device with a hot air gun or
>similar which will melt the 'solder' on all the pins which will then flip
>off the board.

   Hmmm. Well I guess that's one way of doing it. But I take stuff like
this off by heating the pins one at time and slipping a piece of very thin
metal under them so that they don't restick to the circuit board. I take
off 20 something pin surface mount devices this way in a matter of minutes.
 It doesn't mess up the board or part (I reuse both).

   Joe
Received on Fri Dec 03 1999 - 23:03:14 GMT