General > General Technical Chat
How CERN made circuit boards in the 1970s
PKTKS:
--- Quote from: SilverSolder on June 21, 2020, 11:19:06 am ---
Art...
But, in fairness, what we do on computers today is art too... the tools have changed, is all. There is something satisfying about working by hand, though.
--- End quote ---
Agreed.
If the COVID19 isolation gets me too bored...
I still have some left overs from that times... ::)
I will have a very good nostalgic time by just
doing schema on paper and making my board
all by hand...
Paul
SilverSolder:
--- Quote from: PKTKS on June 21, 2020, 11:27:57 am ---
--- Quote from: SilverSolder on June 21, 2020, 11:19:06 am ---
Art...
But, in fairness, what we do on computers today is art too... the tools have changed, is all. There is something satisfying about working by hand, though.
--- End quote ---
Agreed.
If the COVID19 isolation gets me too bored...
I still have some left overs from that times... ::)
I will have a very good nostalgic time by just
doing schema on paper and making my board
all by hand...
Paul
--- End quote ---
Very good! :-) I go out in the garden and get stuck in when I feel like that.
Working with a computer can sometimes feel like you are using training wheels on a bicycle even if you know how to ride...
PlainName:
--- Quote --- the tools have changed, is all
--- End quote ---
Processes have changed. When I did manual layouts like that, every board was checked by two people, preferably neither of whom had done the schematic or layout. One person would call out a pin on the schematic and the other would trace that on the layout and say what else it was connected to.The first person then ticked off the connections (maybe that's what the schematic in the photos show - not the layout persons reference but the checker's). At the end, there should be no unticked pins on the schematic and, of course, any wrong connections would be picked up during checking.
No-one does that now because the ERC is infallible. A bonus of the manual checking was that every detail of the layout was covered so incorrect footprints or things in the wrong place would likely be picked up too.
I think it's pretty different. Perhaps a similar thing is writing a book: doing it when a typewriter was state of the art vs a word processor now. And accessibility - anyone can write and publish a book, just as anyone can design and make a PCB, but back then you really had to be 'in the trade' to get anywhere (or even know how it's done).
basinstreetdesign:
--- Quote from: cgroen on June 21, 2020, 10:18:47 am ---
--- Quote from: TerraHertz on June 21, 2020, 08:56:11 am ---
--- Quote from: ebastler on June 21, 2020, 06:52:35 am ---I think the author did indeed mean "spatula" -- not for the cutting step, but to be used instead of a finger (finder?) when placing and rubbing down the trace.
--- End quote ---
But then you'd be perpetually swapping back and forth between the blade and spatula. You need the blade for every single run of tape, since it has to be cut off neatly. Holding the roll in one hand, you can use the blade to pick the tape end off the roll (can't touch the sticky side with fingers!), place the starting end precisely, then gently position the tape as you proceed along. When done just run a finger or fingernail along it to fix it firmly. Never putting the scalpel down.
A smooth, blunt tool was used for transferring Letraset text though.
--- End quote ---
That was exactly how I did it in the 80's! We did the layouts in 2:1. Those were the times....
--- End quote ---
I oversaw this exact procedure during the 70's - 80's in a small video manufacturing outfit. We had just acquired a white printer to get check prints from schematics. To make production documentation so the assemblers could see what part went where on the boards, I found that a paper print of the pcb could be made by spreading a D-size sheet of printer paper on a table (or on the floor if there was no clear table space) sensitive-side up and pinning the two-colour pcb artwork on it. After about 30 min the artwork was put away and the paper was fed through the printer, processing it with ammonia. The blue side (which was always the solder side at our place) would mostly fade away due to the high green light content of the fluorescent lights but the red component side would be printed in high contrast. Then I would just mark it up with coloured markers and voila'. It was a lot faster than getting a draughtsman to do up a pretty drawing of the board.
I will never forget that experience. :popcorn:
schmitt trigger:
The smell of ammonia and other chemicals in the print room?
Indeed, one could smell a print job waaaay down the corridor.
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