[time-nuts] Working with SMT parts.

Bob Stewart bob at evoria.net
Thu Aug 11 14:20:54 EDT 2016

Hi Bob,
You want to get something along the lines of ebay item 272331719376 or 262202931320.  The boom is pretty important, otherwise how do you get your boards under the microscope if they're not very small?  Some time ago, I got a Bausch & Lomb Stereo 3 with 10X oculars and a 0.5 barlow.  The zoom scale on the scope reads 0.7 to 3.  This, combined with the 10X oculars gives it a zoom range of 7X to 30X.  This is a bit strong for doing PCB work, so the 0.5 barlow cuts that in half to 3.5X to 15X which is just about right.  I leave the boom at the right height to do soldering on the bench, but don't have the lateral thumbscrew on the boom tightened, so I can move the scope left and right or out of the way.  I wouldn't pay extra for a fancy light system like you'll see on many auctions.  Instead, I bought an LED light ring to go around the barlow lens on the bottom.  It has a brightness control, so it works out well.

As far as the board suppliers, I tried ExpressPCB at first, but they're pretty expensive, and you're stuck with their board size.  So, I switched to OshPark.com.  They don't supply proprietary board design software, which is fine, because there is a free version of Eagle, or you can use Kicad like I do.  (Kicad can output Gerber files.)  I believe that both Mouser and DigiKey have free board design software, as well.  But, the risk with those is that they either go away or become pay systems.
Bob - AE6RV


      From: Bob Albert via time-nuts <time-nuts at febo.com>
 To: Discussion of precise time and frequency measurement <time-nuts at febo.com> 
 Sent: Thursday, August 11, 2016 12:24 PM
 Subject: Re: [time-nuts] Working with SMT parts.
What are the important parameters regarding purchase of a stereo microscope?  I see some on ebay for around $50; are those good?


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