I've been working on a high-power HF autotuner design that I'd just
about shelved because of the necessity of soldering the DDS chip. (it
uses an internal RF source to power the phase detector)

This thread has helped a lot. When time permits I may order up some
parts and give it a try. I have a good-quality magnifier lamp and a
fine-point temp-controlled pencil, what I don't have is OEM eye lenses
and flexible finger joints... ;-)

Jim, N7CXI

ken scharf wrote:
Ian White GM3SEK wrote:
ken scharf wrote:

Now to solder those chip caps and resistors! (They should be easier,
the AD9851 was the worst part to place with the tight spacing, all the
other parts have lead spacing at least twice as wide).

It's MUCH easier to begin with the easy parts! Start with the largest
chip caps and resistors, continue with the rest of the simple passives,
and then the largest ICs (largest pin spacing).

Finally, when you've honed your SMD skills, solder the large ICs with
the small pin spacings.

And give up the industrial-strength coffee for the duration :-)


For some reason the instructions that came with the DDS-60 kit have you
solder all the ic's on first, then the resistors and caps.

After thinking I had done a good job on the AD9851 I put the board under
my binocular microscope for a close in look. I saw what looked like
microscopic solder bridges between the chip leads. I was able to remove
these with a stiff piece of paper slid between the chip leads. I still
see strange 'hair like' structures all over the board under the
microscope. I may be seeing dust, bits of flux, who knows! The
microscopic world is strange, especially in 3D.