Re: Desoldering surface-mounted components: Advice sought

["Robert L. Doerr" <rdoerr@bizserve.com>]

Try Jameco.  They have inexpensive SMD equipment.  You can get a special
Tweez Iron for heating both sides of the chip for around $70.  They have a few
different tips for them as well.  They are on page 85 of their current catalog.
In the past I've used something like this to remove and old chip and then used
a regular soldering iron with the smallest tip I could find to solder each lead
on the new chip one at a time.  You must take a lot of care since it is VERY
easy to create a solder bridge.  Here is the Jameco web link for the iron and
the part numbers for the tips.

http://www.jameco.com/cfm/viewdesc.cfm?part_num=137031

137031 - TWZ226 SOLDERING IRON,TWEEZER,W, 120VAC,
REMOVABLE TIPS SMT

137058 - XY55 - TIP,TWEEZER,.079",P/N 137031 FOR TWZ

137066 - XY56 TIP,TWEEZER,.393",FOR P/N 137031 526EZ

137040 - XY57 TIP,TWEEZER,.590"FOR P/N137031TWZ

I've also seen people get away with just removing the old chip by gently prying
each side up while warming it after using a solder wick to soak most of the
solder.  It's a cheap way to do it but I would recommend getting the correct
Iron above if you plan to do more than a few.  I've also heard that a way to
remove surface mount components from a SCRAP board is to hold it upside
down and heat the back side of the board with a propane torch.  As soon as
the solder melts the parts just fall off the board.  Since it is heated from the
back side it can be done without damaging the parts.  The PCB itself is toast
though (Literally).

Robert

stephen e buggie wrote:

> Has anyone mastered the technique of desoldering surface-mount components?
> I want to desolder/replace an IWM disk-drive chip from a IIgs board.
>
> Thanks to Hank Levinson's expert tutoring, I now routinely replace RAM
> chips soldered to boards ---- using sockets in the replacement. But the
> IIe/IIc rams are DIP-packages mounted traditionally in holes.
>
> I've subscribed to SURFACE MOUNT TECHNOLOGY magazine for the past year,
> but there is a total lack of advice on manual removal or replacement of
> SMT components.  The magazine is for original manufacturers only.
>
> HELP REQUESTED!  Even trial-and-error attempts can be reported so that I
> won't make the same errors......    Thanks,     Steve Buggie
>
>  **=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=**
>  ** Stephen Buggie  UNM-Gallup,  200 College Road,      Gallup NM 87301 **
>  ** buggie@unm.edu      IIgs/IIc/IIe  voice: (505) 863-2390 or 863-7504 **
>  **       Douglas DC-3.....Volkswagen Beetle.....Apple ][ forever       **
>  **=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=**

--
------------------------------------------------------------
Robert L. Doerr (MCNE, MCP, A+)
26308 Cubberness
St. Clair Shores, MI 48081
Tel: (810) 777-1313
e-mail: rdoerr@home.com
WEB Site: http://www.robotswanted.com
"Keeping Personal Robots alive!"
Heathkit HEROS (Jr, 1, & 2000), Androbots, & MAXX STEELE.
------------------------------------------------------------