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Homebrew PCBs

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Message

Re: Surface Mount

2009-02-20 by jerrytr2.com

So I have been dragged kicking 
> >and screaming into the 21st century.
> 
> Ain't Technology wonderful?

*** It sure has come a long way since the 6V6GT's and 5U4GB's of my 
youth...

> Yeah, now try to measure them.  Seems to be the 50 dollar solution 
and
> the 350 dollar solution, other than the 10 dollar ebay tweezers
> (only).

*** I bought the $10 ebay tweezers.  They work pretty good, except 
that the tips are pretty dull/rounded, and the  pivot a just a little
wobbly.  Also, my DMM that matches them ( a Fluke 10 ) doesn't do 
capacitance.  I have another credit-card sized DMM that does do C, 
but it has it's own can't-change-em test leads.  Lucky I'm a chinese 
food fan, and long ago mastered the use of chopsticks :).  

 
> You'll either want a small tip (almost a needle) soldering pencil 
for
> the leads, or you'll want to tin-lead coat the pads before 
soldering.

*** Probably tin-coat before.  I just ordered flux and a roll of 
20-mil rosin-core 63/37 solder.

> Very find gauge solder is also a must.  I find that upon occasion, a
> larger soldering iron to solder multiple pins at once, and a
> desoldering tool (built in air pump kind, not spring release) cleans
> up things nicely.  NOT elegant, I know.

*** I ordered some rolls of solder wick, with just that in mind.

> 
> If you had the right stuff, then a syringe of solder paste and your
> hot air pencil would be the optimum method.  (Right stuff defined as
> right tools and paste, etc...)

*** I did order a kit of solder paste from www.celeritous.com.  The
lead-free kind, because paste has to be kept in the fridge, and I 
really don't want to keep a tube of lead in with my sandwiches!
But further research into the characteristics of lead-free solder has
me thinking that I might want to skip that. Maybe get one of those
little coolers with peltier junctions just for the solder paste.

> 
> Yeah, possible to do, messy, and then there's the matter of vias...

*** Close inspection of my scrounged TQFP-64 convinces me that I 
cannot put any through-holes under it, because there is no space for
the height of the wire sticking through.

> 
> An alternate option is to use a carrier, such as the schmartboard
> carriers, and go from there.  Chip will be on a carrier that's 2
> inches by 2 inches. 
*** I looked at that.  Really porks out the part...

                                    - Jerry Kaidor

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