On Thu, 1 Aug 2013 12:54:55 -0700 (PDT), you wrote:
>1980s technology:
>
>Back in the day, one of my CBer friends got some plans for a 2-transistor push-pull RF amplifier that used a double-sided PC board. He had no way to make a 2-sided board with both sides in registration.
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>So he made two one-sided boards and carefully drilled the four corner holes to mount the board(s) in the chassis, and then stuck them together and drilled the through holes.
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>It worked.
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>I was amazed.
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>However, I was more amazed when one of the RF transistors literally exploded and the amp kept working, but only at half power.
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>
>Nowadays you can buy this exact same PCB from a number of vendors, pre-drilled and with thru-plated vias. Progress .... along with the 21st century invention of "competition" amplifiers that are made by cutting PCB "islands" and glueing them to a substrate, allowing the builder to construct multi-pair amps Manhattan-style / dead-bug style with essentially no need for etching a board. Only a hacksaw is required, or big tin snips, or a shear brake.
On the other hand, this is a homebrew PC board group. The argument
for doing boards yourself comes down to money and time. Generally, a
board you do yourself is less expensive than otherwise. Quality may
be an issue, however. A microprocessor/FPGA board, double sided,
about 4.5 by 6 inches, costs either 22 dollars cheapest in China, or
some 65 to 120 dollars made in the good ol' USA. We're talking
delivery time as well.
With printable artwork, and nothing else needs doing, I can have that
board etched, ready to be epoxied together, at the end of the day for
about 3.50 USD for material, not counting the etchant, toner and
epoxy.
24 hours later, the glue has set, and it's stitching top and bottom
together, say half a day doing that, half a day mounting parts (a
slight bit more than needed), and in theory, in 3 days, I have a board
that is done.
China takes a bit longer, and I'd really hate to have sent them a bad
layout without resorting to prototypes first.
However, if I want solder mask, plated through holes, and silk screen,
they get the job.
Harvey
>
>73
>Jim N6OTQ
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