Dated PCB design technique

Maybe everybody knows how PCB were designed some (ehem maaany) years ago, but I didn’t (no, I am not that young anymore, but still I never learn it) so I wanted to share this video, it is pretty interesting.

https://www.youtube.com/watch?v=7weZ0TNRcuw&feature=youtu.be&t=398

Have fun!

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I did this at home in the 80s. Of course with less professional equipment. Ordering multilayer PCBs over the internet (what is a computer ??) was out of the question.
I still have the equipment for single sided PCB production and I am using it for fun.

But I have stopped using transfer symbols and tapes before exposure !

Anyway this is a nice film. Perfect for those who complain about missing comfort/functions in KiCad :wink: :wink:

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Tapes? Looxury! We had to draw traces with wide tip drafting pen. Really. But we had preprinted pads for DIP footprints we could stick on.

Then send it off the photo shop to get it reduced 2x on a negative. We could do double sided by aligning front and back negatives then stapling them.

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And we used to put on alignment targets and label layers 1-2-…with a window in the copper so that we could check that the manufacturer hadn’t got the stack wrong - very easy to do with films

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I remember back in the middle ages (mid 90’s) OrCad had an automated layer label tool. I sort of recreated it for 2 and 4 layer boards:
LayerIcon04.kicad_mod (2.8 KB) LayerIcon02.kicad_mod (2.0 KB)


2020-07-24 11_07_41-Window

I forget how I did the 4-layer label (I did them pre-v4 because I kind-of remember converting them to the .pretty format), as I can’t for the life of me figure out how to turn on inner layers in the footprint editor (KiCad v5.1.6-1 on Win10). But, I probably should add copper keepout zones above and below the inner layer labels to keep them from accidentally being obscured.

mmm this kind of explains this in KiCAD, I understood why it was for, but I never had to used for anything.

My brother had some of this when I was in the school (don’t remember for what, but definitely not electronics)

Until I saw the video and from the comments I realized that the layouts where done on a different scale (2:1 or 4:1) and that explains all the nice details, I try to use those transfer symbols as a kid and it was a pain to get something nice (I pressed with a pencil on the back to get the symbol on a piece of paper, probably the wrong technique also).

In 1980-81 I worked for a small electronics design firm. I drew schematics by hand for my parts of the product we were working on, and a draftsman drew the final schematics and did the board layouts using these same techniques.

You can’t, but KiCad understands inner layers in footprints. You can add an item to some layer and change the layer manually with a text editor. Maybe you did that back then?

Around then PCBs were designed by specialist contractors. They drew on film in red and blue crayon and then taped up with crepe tape and transfers. They all drove Lotus cars and chain smoked, probably dead by 50
They were replaced in the mid 80s by in house design gurus using Redac Visula on Sun workstations

Unluckily for us, they are not here to comment.

Yeah, no traces of them. :wink:

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Manual PCB layout was a really high stress job, lots of all night working. These people used to charge a fortune. Younger people on this forum would be horrified at just how expensive multilayer PCBs used to be. Why alternatives like wire wrapped backplanes made any sense

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I do still add layer markers to my 4 layer boards if there is unused room on a boarder, had a board house that flipped layer 2 and 3 in the past, so makes me feel safer to have a really idiotproof check on it.

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Did he use them for model railways (railroads) ?

I honestly have no idea what he used for, but I do not remember any model trains or railroads from my childhood, I may be blocking it :stuck_out_tongue:

Just curious, I sort of remember using similar sheets to add “pinstripes” to some fancy paint schemes on my model trains (but it was a VERY LOOOOOONG time ago) in the days when I used them for making PCBs. The versions I used were 1:1 scale and used as a “contact resist” on simple single-sided circuit boards.

I do faintly remember trying to use those patterns to do a PCB once (very long time ago, as a curious kid) but I believe I try to attach it to the copper directly and it didn’t really work. Afterward I got a black marker and draw my traces as needed. Faster, easier, cheaper(?).

in the 80s I tried this too. I wasnt very successful with markers on copper. They either didnt cover enough or bloated. For some years I used the symbols shown above directly on the copper with narrow tape as tracks and black marker for fills. :unamused:

It took until the nineties until I was able to build a simple UV device and copy RULE Layouts to transparent drawing paper in a copy-shop. This gave me a 50% success quote. :woozy_face:

Today I have a cheap laser-printer wich I configure to maximum black - really, really maximum, deep black !! This works fine.
I am certainly not able to produce multilayer-finepitch PCBs but I can have the PCB an hour after printing.

However, as a beginner today I would surely save a lot of ruined PCBs and clothes and order via internet … :slightly_smiling_face:

But then they would miss out on the fun of drilling holes in their fingertips :slightly_smiling_face: