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Why Are Printed Circuit Boards Usually Green? (2017)

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Re: Why Are Printed Circuit Boards Usually Green? (2017)

#62

Earlier quoted context omitted.

I suspect it's a deliberate choice both as a fashion statement and to discourage repair. It's interesting to see a similar phenomenon with desktop PC motherboards: "gamer" or otherwise "enthusiast" boards are often a non-green colour and come with superfluous design elements (like plastic covers over the actual components, which sort of remind me of the engine covers on newer cars...), while both the ultra-cheap preb…

I blame case windows for this. The last desktop I built, it was a chore finding a case that didn't look stupid, and I eventually gave up on a normal motherboard, as anything with a z170 chip set looked like it belonged in a transformers toy. And while people definitely geek out over servers, it's nearly all about specs. After all, why make something that gets hidden away in a rack in a DC look pretty? I suspect that…

Ironically enough, case windows were created so people could show off the components inside, but now they're only showing off the covers on them.

Re: Why Are Printed Circuit Boards Usually Green? (2017)

#63
post #8

Apple PCBs are all black nowadays. They probably went all they to make the black pigmened oil as good as green.

I suspect it's a deliberate choice both as a fashion statement and to discourage repair. It's interesting to see a similar phenomenon with desktop PC motherboards: "gamer" or otherwise "enthusiast" boards are often a non-green colour and come with superfluous design elements (like plastic covers over the actual components, which sort of remind me of the engine covers on newer cars...), while both the ultra-cheap preb…

I doubt it has anything to do with repair. When you’ve got a 18 or so layer PCB, probably with microvias (invisible if they’re in pads), and very closely spaced QFN and BGA-packaged parts everywhere, soldermask colour is the least of your problems. So much of the design is on internal layers inside the board and so much interconnection to internal layers in pads (if using microvias) and under BGAs that being able to easily see the top and bottom layer traces easily would give you very little to go on. You’d really need design files to do anything more than just reflowing the odd part...

It probably is a lot to do with fashion though. It’s literally one of the only reasons that I always specify blue or black soldermask at work - just looks a lot cooler. Green boards just have that late-90’s electronics look.

Re: Why Are Printed Circuit Boards Usually Green? (2017)

#64
post #37

Earlier quoted context omitted.

This research is why we were sold computers with green-colored phosphor monitors back in the 80s. I'm not going back, but if you're into it, maybe try: https://marketplace.visualstudio.com/items?itemName=gerane.T...

At some point people started switching to amber. If above research is correct, then why was amber deemed preferable?

I don't know why it was initially deemed preferable, but as a user it was really nice to have something different for a change.

Re: Why Are Printed Circuit Boards Usually Green? (2017)

#65

> 1. Green can relieve visual fatigue and aid in inspections > In the early days, due to technological restrictions, quality inspections relied on workers manually checking the boards with their bare eyes. Squinting at tiny circuits all days is tiring work, but neurologists and psychologists agree that the wavelength of green light has relaxing effects on the body and can reduce fatigue. Additionally, they have found…

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Re: Why Are Printed Circuit Boards Usually Green? (2017)

#66

The article mentions that there are "even mixed color boards", does anyone have a photo of any? I did a cursory search and didn't see any, but am interested in how these looked.

I recall reading that the map of Italy on the back of an Arduino Uno is tendered using white solder mask, because traditional silk screens did not provide enough resolution.

Re: Why Are Printed Circuit Boards Usually Green? (2017)

#67

Earlier quoted context omitted.

QWERTY keyboards? Built so mechanical typewriter keys would not hit. Used for computers.

> Built so mechanical typewriter keys would not hit. Most likely a myth. There’s tons of articles on it, but here’s one to get you started: https://www.smithsonianmag.com/arts-culture/fact-of-fiction-...

The authors of the paper seem to believe that the object would have been to slow down the typist (had the jamming hypothesis been correct). The opposite would have been true. Increase the difference of the angle of approach of successive hammers, and you decrease the chance of jamming and increase the speed. I'll admit that the Z-SE ("dot-dot-dot-space-dot" in early American Morse, with the length of the space/mark mkaing the difference) problem makes some superficial sense, but then there's a corresponding R-EI ("dot-space-dot-dot") and others that aren't reflected on the QUERTY keyboard. (The original Morse code needed far too much space-length discipline, which is why it was replaced fairly quickly, even in the NIH-heavy USA.)

Re: Why Are Printed Circuit Boards Usually Green? (2017)

#68
Soldermask is most commonly green in color but nearly any color is possible

Another reasons: based on old military requirements and standard, UV (ultra-violet) sensitive photopolymers and LPISM technology patent story

https://electronics.stackexchange.com/questions/82669/why-ar...

Re: Why Are Printed Circuit Boards Usually Green? (2017)

#69

Earlier quoted context omitted.

I used to buy some quadcopters and parts from China, and there is a particular board revision that was horrible. It was easily identifiable because it was red. I wonder if this was a prototype or early production run that just kept going. I was buying this particular model for about two years, and the reds would show up during this entire time.

Eachine? Or Syma? Both have a version in red that's bad.

Cheerson CX-10. Great quad for teaching, but very unreliable. Also, most parts can easily be scavenged from other ruined quads but the aftermarket propellers are horrible.

Re: Why Are Printed Circuit Boards Usually Green? (2017)

#70

Earlier quoted context omitted.

Wow, gold everywhere. Even the ICs have gold-plated pins... that's not something I've seen before.

They're beautiful. Good luck oxidizing any of that in normal environments, those scopes will outlast the people that built them. Old computer hardware used to be just like that, I would buy the boards by the pound in the 70's for parts. Gorgeous stuff.

Annoyingly the IC sockets tend to oxidise if the board doesn’t! I’ve lost count of the number of them I’ve had to replace in my life.

If it wasn’t for mechanical switches, pots, contacts and some dubious thermal design I imagine the kit would last for 100 years easy. I have 40-50 year old stuff on my bench in daily use.

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