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Designing for longevity questions and request for long-lived extremophiles!

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MadScientist:
Given the budget , most electronics can be designed to operate well past the end of their engineers life or to survive conditions that would quickly extinguish human life.

The reality is that cost constraints drive everything , why make a telly that can survive for 50 years , there no customers for that device

Today most half decent electronics lasts quite a long time , I can’t remember the last time I dumped a non functioning TV. I have MacBooks that are 10 years old , etc etc

Tomorokoshi:
Old machines that just keeps working like the HP equipment referenced above have likely been repaired at one point or another. What keeps them around is the relatively easy access to clear schematics, part lists, and spare parts. One strategy is to use widely available parts that have been manufactured for a long time.

The schematic is only a mnemonic of the circuit. It doesn't completely represent the realization of the implementation. (To use Blaauw's terminology). The schematic can miss influences such as:

Environmental:
- Temperature
- Humidity
- Dust contamination
- Aging

Chemical:
- Corrosion
- Tarnishing

Mechanical:
- Flex
- Vibration
- Spacings

Electrical:
- Out of range inputs
- Out of range outputs
- EMC in all its various forms
- Frequency of operation

User:
- Foolishness
- Idiocy
- Ineptitude

Some of these can be mitigated using well-known and understood design practices.

For instance:
- Instead of potting the entire assembly, conformal coating will provide a lot of protection without making serviceability impossible.
- Protect all inputs and outputs with filters and devices to limit the input and output voltages, currents, and frequencies to acceptable levels.
- Use an enclosure that provides appropriate protective features.
- Operate parts well inside their ratings. Note that some parts may drift more when operated well below their ratings.
- All the above influences can change the operating value of the part in various ways.
- Add redundant circuits in critical areas.

That said, it isn't too difficult to find equipment that is quite old that never needed servicing. However, it's easier to find examples of newer equipment that failed for preventable reasons.

chickenHeadKnob:
If you havn't seen this before:

Audioguru:
I thought you were asking how will I last a long time.
It is because I feel and act much younger than my age (73), my wife keeps me young and I have routine maintenance from my doctor and medications.

Nusa:
1)  Are there more good examples of electronic systems still being used as workhorses today?
Tube-based amplifiers are still valued and used by many musicians and audiophiles. Including antiques.

2) Does potting compound help with extending life?
Maybe. Depends on nature of the circuit and the environment it needs to operate in. On the flip side, a broken device that is NOT potted is more likely to be economically repairable if it fails.

3)  What is an example of a device DESIGNED to last a very long time, decades+?
Virtually all commercial avionics. The design life of most aircraft are 30+ years.
A lot of higher-end electronics test equipment. There's a healthy market in hobbyist arena for still-functioning test equipment from decades ago, as the new stuff is out of their price range.

4)  Other than heat, moisture etc, all the standard common sense stuff, what design considerations can be taken to extend component life if money was not as big an object?
5) Any good reference materials for very long lasting electronics?
NASA has a lot of public documentation on design standards for space equipment.

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