[hpsdr] Bare Boards

Fri Feb 16 07:34:41 PST 2007

Weller WSD81 + WSP80 handle X2  ~ $260
Weller ETS tip -  X4 ~ $20
Fine curve tip tweezers - approx $15
Anti-static work mat - approx $25
Kester Water Soluable Flux
Kester No-clean solder paste
Dyanscope LYNX Stereo Zoom Microscope
with Boom and Ring Light ~$8000

Setting the parts on the board and handing to the rework girl in the
corner
and admiring her work under the microscope  $Priceless   

I am never afraid of a little work....... :-)

Peter Hughes
N7BMG   

> -------- Original Message --------
> Subject: Re: [hpsdr] Bare Boards
> From: "Philip Covington" <p.covington at gmail.com>
> Date: Fri, February 16, 2007 9:29 am
> To: "Bill Tracey" <bill at ewjt.com>
> Cc: hpsdr at hpsdr.org
> 
> ***** High Performance Software Defined Radio Discussion List *****
> 
> Hi all,
> 
> Here is a quick list of the equipment I use for soldering.  I have not
> found anything that I would not attempt yet.
> 
> Weller WES51 Soldering Station - approx $120
> Weller ETS tip - approx $5
> Fine curve tip tweezers - approx $15
> Dental Pick set - approx $15
> Stereo Boom Arm Microscope (5x-10x) - approx $275
> Toaster Oven - approx $30
> Hot Air Gun (1" dia nozzle) - approx $20
> Dwyer Temperature Controller w/ thermocouple - approx $30 used
> Halogen lamp - approx $20
> Anti-static work mat - approx $25
> Dental mirror - approx $5
> Kester No-clean flux pen
> Kester Water Soluable Flux
> Kester No-clean solder paste
> 
> I use the dental picks for inspection.  By dragging the dental pick
> across the pins of the fine pitch parts I can quickly hear if there is
> a bad solder joint.
> 
> I also use one of the dental picks as an electrical probe when debugging.
> 
> I use the dental mirror for inspecting the sides of components,
> especially QFN leadless stuff.  I use the dental mirror under the
> microscope at a 45 degree angle.
> 
> The hot air gun is great for removing one component.  I shield the
> rest of the components with heavy duty aluminum foil and place the
> thermocouple probe right at the component I want to remove.  I space
> the heat gun about 1.5 " away from the part to be unsoldered and watch
> the temperature.  When it reaches about 225 C, I remove the part by
> tapping it with the dental pick.  The above procedure also works well
> for soldering the QFN parts.  If I have more than one to do I use the
> toaster oven instead with the same temperature probe.  I manually
> modulate the temperature to follow the Kester solder paste profile.
> 
> I have enough patience to do at most one or two boards myself - but
> pretty much only for the initial development and prototyping.  After
> that, it becomes boring and too much like work - then I'd rather buy
> an assembled board.
> 
> 73 Phil N8VB
> 
> 
> 
> On 2/16/07, Bill Tracey <bill at ewjt.com> wrote:
> > ***** High Performance Software Defined Radio Discussion List *****
> >
> > I'll admit to being surprised at the amount of interest in bare boards,
> > turns out to be running a bit higher than I'd expected it would be.
> >
> > I'd be interested to hear from the folks looking at the bare board option
> > their reason for going that route.  Is it a cost issue?  Or really want to
> > know the technology and figure building the board helps in getting to know
> > how it works?   The ship building feeling one gets putting something like
> > this together?
> >
> > I'll admit I like building these things.  Having built two sets of these
> > and done major repair work (FPGA replacement) on one, I'll happily go the
> > built and tested route on this round of boards.    As others have pointed
> > out, these are not beginner SMT boards.   The first set I did,  I did w/o a
> > microscope using a fine tipped iron.  Doable but right at the margin of my
> > skills w/o a microscope.   The 2nd set I did with a microscope and a mix of
> > fine tipped iron and hot air and paste technique - this one was much easier
> > with the microscope - I'll never consider doing 100+ pin 0.5mm pitch parts
> > w/o a microscope ever again.     The other parts on the board that are
> > somewhat troublesome to hand assemble are some of the resistor packs which
> > are a leadless package (Personally, I do hope there's a special place in
> > hell for the geniuses that came up with leadless packages)
> >
> > I don't mean to discourage anyone from going the bare board route if that
> > is what they want to do.  Just interested in folks reasons for building
> > their own and want to make sure folks are aware how small/tight pitched
> > some of the parts are.     Actually I'd hope to recruit some of the folks
> > with the skills and tools to build this kind stuff by hand to get involved
> > in some of the future projects.
> >
> > Cheers,
> >
> > Bill  (kd5tfd)
> >
> >
> >
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