Surface Mount Components in Kits

[Barry A. Watzman]

Not all chips, not even all SMT [surface moung] chips, are problems, agreed.

But the high density QFP's can't readily be done by hand [and the fact that a very few very skilled people might be able to do it doesn't make it possible to market a product requiring those skills to the general public].  And BGA [ball grid array] chips are COMPLETELY impossible for ANYONE to do by hand, the contacts are under the chip itself and not accessible.

The problem is that that there are entire classes of products for which modern, state-of-the-art products can't be built without using at least some such components.  We are talking mostly about digital stuff, agreed, so perhaps ham radio kits would be among the least effected.  But test equipment, computers and modern "audio" equipment [with audio and video digital signal processing] all fall into this category.

----------
From:  Mark Moss [SMTP:kc8dei at SOFTHOME.NET]
Sent:  Thursday, April 22, 1999 8:14 PM
To:  HEATH at LISTSERV.TEMPE.GOV
Subject:  Re: Surface Mount Components in Kits

>-----Original Message-----
>From: Barry A. Watzman <Watzman at IBM.NET>
>To: HEATH at LISTSERV.TEMPE.GOV <HEATH at LISTSERV.TEMPE.GOV>
>Date: Thursday, April 22, 1999 5:47 AM
>Subject: Re: Surface Mount Components in Kits
>

>
>The bigger problem is IC's, they CANNOT be dealt with without special
>soldering equipment.


    Not entirly true.  As part of my job, I reqularly replace surface  mount
IC's with a pencil-type soldering station.  Low-end versions, usable for
surface mount work, can be had for under $100 and last much longer than
Radio Shack or other cheap irons.  Only chips in which the leads are located
under the chip is hand soldering a problem.

>The question was asked "how could people repair circuits in equipment >with
surface mount components?"
>
>I didn't say that it couldn't be done, I said that it required >special
equipment - in the over $500 range [way over in most cases].

    See above remarks.

>I believe that you would find that any facility doing COMPONENT level
>repair of SMC [surface mount] equipment has such tools.

    The "special" tools are only used for large chips such as PLCC64
Microproscessors or similar.

>But an awful lot of service facilities these days do only board level
>repair, and do consider all circuit boards to be disposable and just >scrap
them [obviously, it depends on the value and cost of the board, >and what is
on it].

    True.

    The first surface mount device I built at home was done with a small
Radio Shack soldering iron, so it is definitly do-able.  Like anything else,
surface mount soldering takes practice.  Also, a small amount of liquid flux
is very helpful.

Mark Moss, KC8DEI

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