Charleston Receiver Building Party (Long)
metavox at earthlink.net
Mon Aug 31 10:54:02 CDT 2009
Several of us gave up Saturday, August 29th, to build our Charleston
receiver boards instead of meeting at Tippy's Tacos. We ended up with
10 almost complete receivers.
First, I lay awake Friday night as I thought up a way to build a better
arrangement for squeegeeing solder paste through the stencil onto the PC
boards. Saturday morning I started on the new jig and as arrivals came
in we got more and more help on building it up. After some adjustments
it was a good design. Joe Sluz, WS3W, was one of our builders and came
down from Ellicott City MD. Joe had a sharp eye and microscope and put
the final adjustments onto the alignment. He started putting solder
paste onto the PC boards and before long the boards were coming out
ready for parts placement.
We put the parts into little bins and then made enlarged copies of the
silk screen with each page devoted to each part. This was suggested by
John Schwacke to Terry Fox and thence to us. The sheets were punched and
mounted into a loose leaf notebook. As parts placement proceeded, the
sheets were flipped over, the parts were pulled and provided to the
people doing the assembly. Rob Bowers, KA0SER manned the parts bins and
kept Corky Searle, Bill Fenn and Rob Seastrom with the parts and
placement info. Each position had a means to hold the board in position
and a magnifying glass.
As this assembly proceeded, Joe Sluz and Tom Azlin started a group of
seven boards putting one type of part on all seven boards. By switching
between each other they kept from getting stressed out and went through
the parts placement for all seven boards. This approach seemed better
than doing just one board at a time.
We ran into a problem as some of the voltage regulator chips were in the
wrong device package. Those devices were skipped and will be put on
later with a soldering iron.
Joe had good experience using a toaster over as a reflow soldering oven
so he manned the toaster oven and soldered the boards much as one would
do a pop tart. By carefully watching, the solder paste started to look
shiny and once all the paste looked shiny, the oven was turned off.
After a short cooling period the boards were removed. This part went
really smoothly just as if we knew what we were doing.
Then each board needed close inspection to fix solder bridging at the
fine pitch IC leads. One of these fine pitch ICs ended up one lead over
and was moved to the correct position.
The correct voltage regulator chips are on order and should be in this
week and we can get people together to put them on if needed.
Rob Seastrom went out to pick up great pizza for lunch. We had a fun
time working together as we all learned how to do this kind of assembly
work. We had a great chance to meet and work with AMRAD members we have
not worked with before. Hopefully this won't be the last.
I know this is a little long but maybe some future Charleston building
parties can use some of our experience to make it as painless as possible.
P.S. I had ordered a nifty little solder paste printing frame on eBay
and suddenly got a message that the shipment had been voided thus
requiring us to build our own. Sunday night, I got an email that the
shipping had been straightened out and it would arrive this week. Oh
well I can use it next time.
More information about the Tacos