[hpsdr] Bare Boards

[Tobias Weber]

Hi there

> I'll never consider doing 100+ pin 0.5mm pitch parts 
> w/o a microscope ever again.     

I would say: Not even with a 64 pin device! 

0.5mm fine pitch is a quite sophisticated issue. I used to repair many 
Radio/TV devices of the 80s and 90s and started soldering fine pitch with the  
attitude: hey, I can solder anything, I'm a professional! But I had to learn 
my lessons.

Chances of having unconnected pins or diminutive shorts that are not visible, 
not even by eagle eyes, are quite high. Even there is a validated connection 
between pad and pin in the first test, insufficiently soldered pins can loose 
contact later when mechanical stress is applied. In my case a 14pin jtag plug 
caused some pins to go offline, but only time from time. It took ages to find 
these bugs. Finally with a microscope and a medical needle I found out by 
touching each pin that some connections were very easy to do break.

If one is going to solder fine pitch -> buy a used microscope and check every 
pin.

> The other parts on the board that are 
> somewhat troublesome to hand assemble are some of the resistor packs which
> are a leadless package (Personally, I do hope there's a special place in
> hell for the geniuses that came up with leadless packages)

 Bill, I do hope the same !

> I don't mean to discourage anyone from going the bare board route if that
> is what they want to do.  Just interested in folks reasons for building
> their own and want to make sure folks are aware how small/tight pitched
> some of the parts are.     Actually I'd hope to recruit some of the folks
> with the skills and tools to build this kind stuff by hand to get involved
> in some of the future projects.

I am already busy enough with the uwSDR hard/software, but basically, I would 
share my skills if possible.

Tobias
DG3YEV
(member of the uwsdr group)

 1171629104.0