On Sat, 20 Sep 2014 18:25:05 -0700, John Larkin
wrote:

On Sat, 20 Sep 2014 17:22:29 -0700, Jeff Liebermann
wrote:

On Sat, 20 Sep 2014 11:00:09 -0700, John Larkin
wrote:

The best layout people I have worked with were women. True today.

Agreed.

"How It Was: PCB Layout from Rubylith to Dot and Tape to CAD"
http://www.eetimes.com/author.asp?section_id=14&doc_id=1285442

A good light table, and a young body, were necessary for hand-taped
layout.

Yep. I brought in a NuArc light table that I inherited from a
previous print shop adventure. The lighting was superb, fairly cool,
and the table big enough for most PCB's. Something like this:
http://www.ebay.com/itm/321208321135
I dragged it through 2 employers, several long term consulting jobs,
and two home business ventures.

At the time, leaning over the table for hours was not particularly
difficult. Today, it would give me back pains in about 15 minutes.
Yep, a young body was a requirement. As I vaguely recall, the oldest
PCB layout person I knew that did layout on mylar was about 25 years
old.

You also needed a flat table with an overhead UV light, for burning
sepia assembly and fab drawings from the various mylar layers. And a
blueline machine of course.

Yep. I learned the hard way NOT to run the layout and blueprint paper
through the rollers on the Diazit(?) machine. Destroying the mylar
original was not a good thing. I had a sheet of plywood and a loose
glass plate. I would pile everything between the plywood and glass
plate, and take it outside for the exposure. Most of the time, the
registration was tolerable. At one company, we did have a UV light,
but it was constantly being "borrowed" by the CEO's son for his
psychedelic light show parties.

You didn't literally need a UV light. A 250-watt warehouse-type
mercury vapor lamp, maybe 6 feet above a table, worked fine.

A plain old "sun lamp" bulb also worked well. Dunno if
those are still readily available these days, since you'd
think that by now most everybody would be clued into the
skin cancer bit. On the other hand you can still buy a Big
Mac on most any street corner, so who knows?

Best regards,


Bob Masta

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