Alpha Build PARC SNA Update

Finally after spending considerable amount of time tracking down and removing solder bridges and a couple of shorts in the traces, checking the board over several times to ensure no shorts remain, I had to admit it was time for the smoke test.  But first a beer to think about it.  Never have I've been so apprehensive to power up a board.

I'm pleased to say all went well with the smoke test. The 8v and 5v voltage regulators remained cool as was the 8307 and memory chip.  Now it was time to plug in the Mega and following that the AD9850 board.

Almost perfect. I have a bit of a loose connection on the ground for the 12v power supply but that's no big deal.

Current draw for the board alone was .03A.
Current draw for the board and Mega was .11A
Current draw for the board, Mega, and the AD9850 board came in at .21A.

Not sure what the draw should be but there's the baseline for the 2 other Alpha builds underway now.

9850 board in the upper right corner, 8307 behind the left bnc connector and the memory chip to the left of the 8307. The MAR6 amplifier is located just to the left of the right side bnc.  The blue wire passes just beside it.  The rather big looking blob of solder is due to the several ground pins coming through the board to ensure good ground for the MAR6.  Hidden under the blue and purple wire is the ground connections on the other side of the MAR.

Up next is to nibble away the pcb area containing the holes for the LCD.  They are not needed and are in the way for the pin extenders needed to raise the LCD to the proper height.  I'll be picking up the screen tomorrow and once that is working ok it will be time to load up the software and put this puppy through its paces.

So far I have about 9 hours into the build. Lesson for me here is hand soldering with such narrow clearances is not the best methodology to be putting a board together.  Good experience though.

Alpha Build PARC SNA

Started to build the PARC SNA.  The challenge I figured was going to be, and still likely will be, putting it through its paces and hopefully cover off on all the possibilities. But I'm sure our software designer, Dave VE3OOI, has thought of everything and it will be perfect.

However, as with most projects on my bench, there are challenges with each project.  No different with this project either.

This board was etched by a laser machine and it is a very nice looking board. The trace clearances are somewhat tight and the through holes are not plated.  The clearances did present some challenges with a few solder bridges that proved to difficult to remove in a couple of cases. After using a solder sucker and solder wick, the shorts had still remained.  Even under a well lit magnifying glass the short could not be seen. Scrapping with a dental tool in one case did not help but a rub with a small fine wire brush did work.

The other self inflected problem, one that I can never seem to avoid, was, well, stupidity. I knew the via's were not through plated and I was given some fine wire to use where necessary. Yet I still managed to forget this and went ahead and soldered in headers tight to the board when I needed to allow a space in order to apply solder. Gave the solder sucker a really good workout and I'll bet I used up more solder wick on this project than all the others I've done combined. HiHi.  But thanks to the quality of the board, it survived the abuse.

About 6 hours into the build so far and today I shall carry on with installing headers and connecting up the via's