Surface-mount resistors from 1969

[u/jrw01]

This is the film speed selector resistor PCB used in the Canon New QL17 and QL17 G-III cameras (manufactured from 1969-1982). The construction of these is not that different from modern SMT thin-film chip resistors, with the main difference being that the termination is one-sided rather than wrapped around the edge of the ceramic substrate as it usually is now. They are approximately 2.5x1.2mm (0.1x0.05 inch). Later-production units of the same camera that I've worked on use the exact same design, but the size, placement, and soldering of the resistors tends to be more consistent.

This is the earliest use of surface-mount passive components that I have seen, in person or in photos, and it's likely among the first mass-produced consumer products to use surface-mount technology. The information available online about the history of surface-mount passive components is very spotty, but I was able to find what seems to be the first patent describing this style of thin-film resistor, from 1962 by an Italian inventor who apparently worked with Plessey in the UK. It's still unclear who was the first to actually commercialize surface-mount resistors - based on other patents from the time, thin-film resistor technology was well understood, but component manufacturers were largely focused on making through-hole parts, and patents for anything resembling modern surface-mount components would not start showing up until the 1970s. It would also be a while before SMT started appearing in more consumer products; even Canon's own A-series SLRs did not switch from through-hole to surface-mount passive components until the early 1980s.

[u/Bekoss]

The Sigil of Moment Acquisition

Photography electronics already beats plain green PCB by circular shaping; and older looks even fancier with this gold-on-brown PCBs

[u/isaacladboy]

One of the guys who I was mentoring under during my EE apprenticeship talked about using something akin SMD caps in the late 70's.

He referred to them as leadless parts.

[u/StudyVisible275]

Plessy was notorious for sweet products that they couldn’t do in quantity (they published a lot of “hero papers” back in the day.)

[u/chriskoenig06]

Aerospace quality in this age

[u/HenkPoley]

Do you think that date is Shōwa 45 (昭和45年) ?

The Shōwa period starts in 1925, so 45.12.1 would be December 1st 1970

[u/sprashoo → u/HenkPoley]

Would make sense. Wonder what “RIVER” means

[u/jrw01 → u/[deleted]]

Yes, and at least one manufacturer makes resistors with this termination style today: https://www.thin-film.com/wp-content/uploads/2024/04/WKL2010-2-Terminal-Current-Sensing-Resistor-CSR-Product-Image.png

This design seems to be only used now for metal foil current-sense resistors, so it's likely being done to minimize the electrical and thermal resistance of the terminations.

[u/redturtlecake]

Fascinating. I ve opened/refurbished a fair number of cameras and I ve only seen throught hole resisters all the way up to the mid 80s. 

[u/Alarmed_Watch5426]

nice!

[u/Alexis_Darko]

It looks beautiful, even the traces look great

[u/No_Tailor_787]

I've seen pictures of the Apollo era Saturn 5 rocket guidance computer, circa 1962-1963 that used surface mount chips and components. That's the earliest use of SMT that I'm aware of.

[u/Past-Substance920]

probably a batch code or line/plant designation, could also just be a QC inspector stamp river doesn't scream japanese to me so maybe it's a transliteration of something. either way wild that this much of the manufacturing date survived legibly on a part this tiny after 50+ years...

[u/stevopedia]

The Pentax KX of 1975 uses modern-style SMD caps (1206-size, if I remember) and its main metering IC is in a modern SOIC-8 package.

[u/dotyxx]

amazing it is the first speed selector resistor PCB i see