I looked into surface mount and I was taken aback about the $1000's
of dollars to get all the equipment needed.

The resisters in particular are so small they look like fly specks.
You need a binocular micro scope just to see them let alone handle
them. I decided to stick to through hole whenever possible. Some
times the PC board company charges a lot more for over 350 holes. I
decided to experiment with 1/10 watt resisters surface mounted.

The other problem is there are no markings on surface mount
resisters which makes it hard to trouble shoot mistakes in values.

I built a rig on a standard Pana Vise to hold the resister in place
with a small alligator clip while I soldered it.

This is what it looks like.

Paul Lamar


Paul, 1206 and most 0805 SMT resistors have markings. You don't need
 to use the smallest.

David josephson

Thanks for the help David. I guess you have to request 0805 1/4 W.
Digi Key sent me a bunch of 0402's.

0805 is 1.2 mm long  and 2 mm wide. Giant size fly speck :)

0805 is .080 x .050, 1206 is .120 x .060, at least the numbers make inch sense.

I can replace the alligator clip with a sharp point.

I'll have to redo the PC board. Who do you use for PC boards?

Paul Lamar

You have to be very specific. You have to look at tempco, tolerance, power,
etc. There are many different 0805s for instance.

We lay out with Eagle PCB and have boards made at Advanced Circuits
in Colorado www.4pcb.com ... they have a "bare bones" special (no silk screen
or solder mask) that's cheap for prototyping.

David josephson
Thanks again David.


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