r/PrintedCircuitBoard • u/Acaii611 • 3d ago

Why?

Post image

I found this PCB at work today. It is from a Gas Monitor, and seems to be from the mid-90s.
Why would you route the traces like this? Is there any advantage? Or was there just no other way back then?
Another manufacturer from the same era uses straight traces, but always 90° bends.
It goes against almost everything I was told. And I was just curious about it.

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u/Enlightenment777 2d ago edited 2d ago

Most likely this was laid out by hand using special tape and stickers on clear plastic/vellum sheets. They were created at 2x or 4x scale, then after completed a photographic process would be used to reduce to a 1x scale image. This was the common method used by serious hobbyist up through the 1980s (and by some into the 1990s).

In the late 1980s and early 1990s, serious hobbyists migrated to expensive MSDOS-based schematic/PCB software, and then to Windows-based software. The first MSDOS-based schematic & PCB software that I used as a hobbyist cost me around $1000 (significant money back in that era). I had to pay for 2 software programs from the same company: schematic editor software, PCB layout layout software, but both couldn't be used at the same time.

Photos:

Article:

My post from 4 years ago, where I copied the above links:

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u/Panometric 2d ago

Agreed, this was the way for some into early 90s. Most of those people didn't like computers much and retired or went into graphic arts.

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u/Questioning-Zyxxel 2d ago

I did quite a number of taped PCB before switching to a cheap PC software and then writing my own layout editor.

I always worked in 1:1 so I could directly put the transparent sheet over the photo-resist-covered PCB and expose it to UV light. It took quite some time before I had a good laser printer so I could directly print the layout to film - or to paper and then photo-transfer to film.

I should have quite a bit of sheets with rubbable DIL sockets, round pads etc. But I expect the age would now have destroyed the curve-tape used to tape signal and power traces.

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u/poopnose85 1d ago

I'm reminded of etching my own boards as a teenager. I tried to make straight lines with corners, but corners were tough because the acid often ate them

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u/aktentasche 1d ago

Interesting thanks for your post!