[time-nuts] surface mount (was PICTIC II Parts from Mouser)

[Bob Bownes]

Not to mention not having to drill holes anymore. I built a 15Ghz
prescaler over the weekend. Total time from concept to completed (and
operational!) prototype was < 2 hours. No muss, no fuss, just design
the circuit, print out the toner transfer, paste it onto the board,
etch, apply paste & parts, drop into the toaster, er, reflow oven,
pull it out, inspect and turn it on.

You don't even need to go as far as the microscope (though they really
do make the job easier). A simple $10 set of magnifying eye pieces or
a 5x magnifying glass lamp ($30 @ Harbor Freight) does a great job.

Am alternative is a webcam that will focus up close. I hooked up an
old TV camera with a macro lens (ebay, $5) to a video capture USB
dongle (ebay again, $15) and put it on an old retort stand. I can look
at it on the screen on the workbench and even do video capture of the
board. Pretty much the ultimate in cheap magnification.

I covered some of this in a presentation at the NEWS conference last winter.
http://www.fastbobs.com/bob/radio/power_meter.ppt

Bob


On Mon, Jul 19, 2010 at 9:22 PM, Robert J Marinelli <bobm at stanford.edu> wrote:
> Hi Richard,
>
> Yes, used to feel that way - until acquiring a surplus dissecting (stereo)
> microscope, now I actually *prefer* surface mount.  Much easier to move
> parts around, it's easy to apply paste & solder entire boards in a $50
> toaster oven, and access to all the latest parts.  Hard to believe, but
> really is easier once you can clearly see.  For some nice tuturials, see the
> sparkfun website, also the schmartboard website.  Also, when I lay out
> surface mount boards, they tend to be smaller overall, and so a bit lower
> cost.
>
> Please do try with a low cost stereo microscope - it changes everything :)
>
> -Bob
>
> p.s. Finger size is no issue - tweezers work nicely.  Oh and surface mount
> resistors & caps are unbelievably low cost in cut tape, and super easy to
> handle that way.  Much better than loose parts IMO.
>
> On Jul 19, 2010, at 4:59 PM, Richard H McCorkle wrote:
>
>> The TS272CN is an acceptable substitute for the TS272ACN in the
>> PICTIC II but as noted has a higher input offset voltage. This
>> can be compensated for in the second stage by adjustment of
>> the offset trimmer. I selected premium parts for temperature
>> stability in the application. Sorry the manufacturers are
>> making "human compatible" devices obsolete and only carrying
>> over surface mount devices as they go Pb free for the EU
>> market. Makes it difficult to keep up with what's available
>> and harder for amateurs with fat fingers and poor eyesight
>> like myself to build simple projects!
>>
>> Richard
>>
>>
>>> Here we go again!
>>>
>>> The TS272ACN has just gone 'non-stocked' at Mouser.  Will the TS272CN
>>> degrade the performance?  It looks like the difference between the two
>>> is the TS272CN has a higher input offset voltage.
>>>
>>> Ed
>>>
>>>
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>>
>>
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