There's a similar component in Pentax cameras with automatic aperture control. I think it is observing and controlling how far the aperture stops down. Here's a more detailed explanation.
For example, I am currently looking for the function of the ratchet gear that is used in the Nikon F4 to control the aperture.
More precisely, the function of the coupled perforated disk that runs through a photointerrupter and generates pulses.
There's a similar component in Pentax cameras with automatic aperture control. I think it is observing and controlling how far the aperture stops down. Here's a more detailed explanation.
The F4 you're working on is a transition camera from traditional analog mostly controls, to higher degrees of automation for things like exposure and focus control. It's not surprising that Nikon would use custom chips to optimize this.
I guess what I'm saying is ... good luck figuring out all the magic boxes
Context is also important. The circuit diagram in the OP is 1 page of a 176 page document, and 1 diagram in a multi-page explanation of the electrical circuit. It could be considered to be somewhat disengenuous to take something like that out of context and expect anyone to decipher the functionality based on that diagram alone.
Around 1970.
In fact, on those Univac machines, it was also unusual for the user to replace discrete components. It's possible that the US Military had its own ways, but in the commercial world, this absolutely wasn't the way things were done back then. A service tech would come in, yank a module from the machine and put a new one in. These modules may then have been refurbished back at the manufacturer's facilities.
I worked on these in the 90s, while on the French Navy.
When did this end?
Around 1970.
In fact, on those Univac machines, it was also unusual for the user to replace discrete components. It's possible that the US Military had its own ways, but in the commercial world, this absolutely wasn't the way things were done back then. A service tech would come in, yank a module from the machine and put a new one in. These modules may then have been refurbished back at the manufacturer's facilities.
Absolutely not, apart from perhaps very exceptional cases which will be hard to find. It's also likely that in 3d world countries component-level repairs are more usual given the low cost of labor in relation to parts cost. You'd see stuff like USB connectors being replaced etc.
It certainly is, and it only happens/happened in situations where there were very specific requirements. In the case of cameras, a driving force behind this was the need for extreme miniaturization (relative to what was common in the market at the time) and a high degree of complexity, resulting in highly integrated and specialized solutions. This was enabled by the manufacturing volumes and the high degree of vertical integration of the camera makers. This is one reason why companies like Nikon and Canon for some time actually kept up in semiconductor manufacturing (up until ca. 25 years ago).
As far as I'm concerned the main disagreement is that I try not to have expectations of other people that are unrealistic.
I worked on these in the 90s, while on the French Navy. We had complète diagrams at hand, the testing equipment to identify the faulty part (read oscilloscope and multimeter) and the tools and spare to replace said parts.
We also had sub-assemblies in limited inventory, but the discrete ICs and components where more universal.
During a repair, we could not only identify which IC failed, but also which part in it ( namely, which logic gate wasn't working as it should)
I worked for them from 1967-1970. During that time they already had some computers with IC's (Univac 1108) but the one I worked on (Univac 494) was all discrete components. The computers memories were bi-stable ferromagnetic cores, 30 bit octal words. Of course, storage was done with tape drives and large drums with surfaces made of magnetic nickel-cobalt.
You are being too generous. The answer is zero.How many people these days can fix a current-model car at the component level? Close to zero. All you can do is switch out a defective module with a new one. Even if you do something as simple as disconnect the battery, you need to reset the car’s computers to get them working again.
You are being too generous. The answer is zero.
Yes, but that's quite an extraordinary environment. I've done research at a nuclear power plant where they also actively used and obviously maintained extremely well-documented control systems dating back to the 1960s. I'm sure they also replaced individual relays - yes, the control logic was implemented at least in part with relays, not even transistors. 1960s technology employing 1930s concepts. It's not the default, of course.
At the repair café where I'm spending some time, we have the same experience. "Failed" devices due to a faulty operator are fairly common (people forget about a safety mechanism and complain their wood machine does not start, this kind of things), and most of the rest is a failed fuse, power subsystem with a faulty cable, etc.I've done some building and repairing of electronic effect pedals for guitar and of music circuits (amplifiers, simple synthesizer modules, etc). At that level, it is possible to understand the signal flow using a schematic and diagnose problems using a voltmeter and sometimes an oscilloscope, if you have some basic knowledge of electronics and a sense of logical troubleshooting. This is with discrete components - resistors, capacitors, transistors, and simple common ICs like op-amps and occasional use of CMOS ICs, delay chips and so on.
However, it is a lot easier if you already know what the circuit is supposed to do. If you just look at the schematic without knowing whether it's a distortion pedal or an envelope follower, you have to figure that out and break the circuit into its components before diagnosing it.
People who work on such circuits without previous electronics training have a tendency to assume that the most complicated part of the circuit, such as an IC, is the likely source of problems. It's rarely the IC! Problems are far more commonly things like cold solder joints, bad switches, failed capacitors. Just as pandemic lockdown started, my cable modem failed. It's a device full of large custom surface mount ICs that one could never understand - but the part that failed was a 20 cent power supply filter capacitor, the one part I could replace in 5 minutes.
I took a basic electronics course in college, which was enough to teach me what an op-amp does for example. People without that training often think an op-amp is a device full of magic beans and guitar tonality. It's actually a precision high-gain amplifier that does one thing, drive its inputs to be equal. The internals of op-amps are an amazing work of decades of engineering discipline that you don't need to understand to use. The feedback circuit around the op-amp, a bunch of few-cent resistors, capacitors, and potentiometers, is what differentiates one audio circuit from another.
I've done some building and repairing of electronic effect pedals for guitar and of music circuits (amplifiers, simple synthesizer modules, etc). At that level, it is possible to understand the signal flow using a schematic and diagnose problems using a voltmeter and sometimes an oscilloscope, if you have some basic knowledge of electronics and a sense of logical troubleshooting. This is with discrete components - resistors, capacitors, transistors, and simple common ICs like op-amps and occasional use of CMOS ICs, delay chips and so on.
However, it is a lot easier if you already know what the circuit is supposed to do. If you just look at the schematic without knowing whether it's a distortion pedal or an envelope follower, you have to figure that out and break the circuit into its components before diagnosing it.
People who work on such circuits without previous electronics training have a tendency to assume that the most complicated part of the circuit, such as an IC, is the likely source of problems. It's rarely the IC! Problems are far more commonly things like cold solder joints, bad switches, failed capacitors. Just as pandemic lockdown started, my cable modem failed. It's a device full of large custom surface mount ICs that one could never understand - but the part that failed was a 20 cent power supply filter capacitor, the one part I could replace in 5 minutes.
I took a basic electronics course in college, which was enough to teach me what an op-amp does for example. People without that training often think an op-amp is a device full of magic beans and guitar tonality. It's actually a precision high-gain amplifier that does one thing, drive its inputs to be equal. The internals of op-amps are an amazing work of decades of engineering discipline that you don't need to understand to use. The feedback circuit around the op-amp, a bunch of few-cent resistors, capacitors, and potentiometers, is what differentiates one audio circuit from another.
In fairness, the modules are not made to be serviced by anyone including factory techs. It's far more economical to build them in volume for swapout than for someone to laboriously work through component level analysis.
Moreover, with modern automated manufacturing and assembly, the reassembly of a fixed module would be nigh on impossible.
It's analogous to why we don't fix lightbulbs or rebuild oil filters on cars.
I've done some building and repairing of electronic effect pedals for guitar and of music circuits (amplifiers, simple synthesizer modules, etc). At that level, it is possible to understand the signal flow using a schematic and diagnose problems using a voltmeter and sometimes an oscilloscope, if you have some basic knowledge of electronics and a sense of logical troubleshooting. This is with discrete components - resistors, capacitors, transistors, and simple common ICs like op-amps and occasional use of CMOS ICs, delay chips and so on.
However, it is a lot easier if you already know what the circuit is supposed to do. If you just look at the schematic without knowing whether it's a distortion pedal or an envelope follower, you have to figure that out and break the circuit into its components before diagnosing it.
People who work on such circuits without previous electronics training have a tendency to assume that the most complicated part of the circuit, such as an IC, is the likely source of problems. It's rarely the IC! Problems are far more commonly things like cold solder joints, bad switches, failed capacitors. Just as pandemic lockdown started, my cable modem failed. It's a device full of large custom surface mount ICs that one could never understand - but the part that failed was a 20 cent power supply filter capacitor, the one part I could replace in 5 minutes.
I took a basic electronics course in college, which was enough to teach me what an op-amp does for example. People without that training often think an op-amp is a device full of magic beans and guitar tonality. It's actually a precision high-gain amplifier that does one thing, drive its inputs to be equal. The internals of op-amps are an amazing work of decades of engineering discipline that you don't need to understand to use. The feedback circuit around the op-amp, a bunch of few-cent resistors, capacitors, and potentiometers, is what differentiates one audio circuit from another.
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