Newsgroups: comp.robotics
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From: gcouger@olesun.okstate.edu (Gordon Couger)
Subject: Re: STEPPER DRIVER INFO NEEDE
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Organization: Biosystems and Agricultural Engineering at Oklahoma State Univ.
References: <328nsb$h6c@handler.Eng.Sun.COM> <32aurf$7sm@lastactionhero.rs.itd.umich.edu> <32bhgu$gpq@bmerha64.bnr.ca>
Date: Thu, 11 Aug 1994 03:59:08 GMT
Lines: 34

In article <32bhgu$gpq@bmerha64.bnr.ca>,
Attilla Danko <danko@bcarh2d7.bnr.ca> wrote:
>In article <32aurf$7sm@lastactionhero.rs.itd.umich.edu>, ocg@cw-u02.umd.umich.edu (John Roldan) writes:
>.
>-snip-
>.
>A while ago I pulled a couple of dozen cmos memory chips off a soldered board.
>I used only a propane torch, haemostat, and a piece of aluminum foil. 
>
>I stuck the foil to the solder side of the board and cut out a small hole to 
>expose just the pins of the chip that I wanted to desoleder. I grabbed the 
>chip itself with a locking haemostat. Holding the board in one hand, while
>pulling on haemostat hard enough to make the board bend a bit, I waved the 
>solder-side of the board into the flame of a propane torch at the hole in the
>foil. The solder around all 18 pins melted fairly silmultaneously and the 
>chip would come flying out, yanked by the haemostat. Then I'd pick up 
>heamostat/chip from where I'd thrown it and do it again to another chip.
>Of the couple of dozen memory chips I desoldered this way, all of them worked.
>
A quicker method is to lay a towel on a table and a block of wood on the towel.
Heat the solder side with a torch and whack the board against the block.
The chips will fall on the towel. Try is with a junk board first. I have never
done it with out ruining the board. But, I usulay use a oxy-acetlene torch
because its handy.

Gordon


                             Gordon Couger                            
                             Biosystems & Agricultural Engineering              
                             Oklahoma State University                         
                             114 Ag Hall, Stillwater, OK  74074                 
 gcouger@olesun.agen.okstate.edu 405-744-9763 day 624-2855 evenings 
    I do not speak for my employer
