Does anyone know how long the circuits/components in old electrical
equipment generally last for? Equipment like, old TVs, radios,
computers, phones, stereos etc - particularly those made int he 1970s
& 80s?
Could they all in theory still work in 100 years time or would their
components/wiring/circuits etc somehow degrade/disintegrate/fail
after
so many decades?
Many thanks in advance for your advice!

wrote:
Does anyone know how long the circuits/components in old electrical
equipment generally last for? Equipment like, old TVs, radios,
computers, phones, stereos etc - particularly those made int he 1970s
& 80s?
Could they all in theory still work in 100 years time or would their
components/wiring/circuits etc somehow degrade/disintegrate/fail
after
so many decades?
Many thanks in advance for your advice!

who the **** cares. You'll be dead by then anyway.

On Mon, 10 Mar 2008 23:47:50 -0700 (PDT),
wrote:

Does anyone know how long the circuits/components in old electrical
equipment generally last for? Equipment like, old TVs, radios,
computers, phones, stereos etc - particularly those made int he 1970s
& 80s?
Could they all in theory still work in 100 years time or would their
components/wiring/circuits etc somehow degrade/disintegrate/fail
after
so many decades?
Many thanks in advance for your advice!

Do you mean if they're left unused? If in constant use, something
will fail sooner or later.

wrote in message
...
Does anyone know how long the circuits/components in old electrical
equipment generally last for? Equipment like, old TVs, radios,
computers, phones, stereos etc - particularly those made int he 1970s
& 80s?
Could they all in theory still work in 100 years time or would their
components/wiring/circuits etc somehow degrade/disintegrate/fail
after
so many decades?
Many thanks in advance for your advice!

Larger geometry chip internals of that era will last longer than modern
small geometries, due to cosmic ray damage and tin-whisker growth.
Metallisation creep will eventually destroy the older ones with or without
non-hermetic seals and airbourne corrosion ingress


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

wrote in news:c549b51c-7ef3-4b82-9daa-
:

Does anyone know how long the circuits/components in old electrical
equipment generally last for? Equipment like, old TVs, radios,
computers, phones, stereos etc - particularly those made int he 1970s
& 80s?
Could they all in theory still work in 100 years time or would their
components/wiring/circuits etc somehow degrade/disintegrate/fail
after
so many decades?
Many thanks in advance for your advice!


In addition to the comments others have made, there are a couple of other
factors
1) fungal growth, insects, rodents, can destroy electronics.
MIL SPEC equipment receive special coatings and treatments to reduce these
problems.
Most civilian items do NOT.

2) ceramic capacitors 'age', decreasing in value from the last time they
were 'deaged'.
Deaging occurs when the capacitor is heated above the Curie point of the
ceramic.
Aging rate depends on the formulation of the capacitor's ceramic. High K
ceramics can decline in value by as much as as a few percent per decade.
A decade = log(time since last deaging)
So if the cap drops 1% in the first hour after deaging, it drops 2% in the
first 10 hours, it drops 3% in the first 100 hours
it drops 4% in the first 1000 hour, it drops 5% in the first 10000 hours,
etc.

Almost all components age in some way.
When the value of any component gets outside the design limits of the
circuit, the circuit stops working as it was intended.




--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

remove ch100-5 to avoid spam trap

Part of what the OP is asking is whether devices inherently deteriorate * /
self-destruct, even when not being used, or they have to be in use to fail.

The answer is that almost everything eventually falls apart, whether or not
it's in use.

Of all components, I'd expect vacuum tubes to last the longest -- perhaps
hundreds of thousands of years -- simply because glass is highly stable, and
the internal metal elements are in a vacuum, where "...rust doth [not]
corrupt".

* Don't say degrade. Degrade is a transitive verb.

William Sommerwerck wrote in message
news
Part of what the OP is asking is whether devices inherently deteriorate *
/
self-destruct, even when not being used, or they have to be in use to
fail.

The answer is that almost everything eventually falls apart, whether or
not
it's in use.

Of all components, I'd expect vacuum tubes to last the longest -- perhaps
hundreds of thousands of years -- simply because glass is highly stable,
and
the internal metal elements are in a vacuum, where "...rust doth [not]
corrupt".

* Don't say degrade. Degrade is a transitive verb.



I always wonder why air does not pass between pins on the base and the glass
of the envelope. Unless knocked or cold effects they are highly reliable,
despite , i would have thought. glass/metal (even without corrosion) would
be suspect over time

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

wrote:

Tubes do not fail from not being used, unless they are broken or leaky

Not actually true. Over time their characteristics drift from ionic
contamination mainly IIRC and the emissivity of the cathode gradually
reduces too. I've seen tubes that have actually gone zero emission even
though the filament still works.

Graham

"N Cook" wrote in :

I always wonder why air does not pass between pins on the base and the
glass of the envelope.
It can't. There is no room.

Unless knocked or cold effects they are highly
reliable, despite , i would have thought. glass/metal (even without
corrosion) would be suspect over time

The metal is first treated to form a layer that will chemically bond with
the glass.
A layer of glass is then put onto the lead. It 'wets' the lead, bonding to
it strongly. This glass must have the SAME coefficient of expansion as the
metal!

In general, there may be several different layers of glass applied, each
with a slightly different coefficient of expansion.
Finally, the base of the tube is molded around the set of leads, the
electrodes are spot welded to the leads,
the envelope is applied, the vacuum is pulled and the tube is sealed and
the 'getter' is fired'.




--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

remove ch100-5 to avoid spam trap

TVs and radios with valves ( tubes) close to for ever but unfortunately
limited to their weakest link, the capacitors. They are good for 35 years
then dry up.

Modern electronics are probably good for 20 if they are of the highest
quality. Computers somewhere around 8 years because of crappy capacitors on
the motherboards. MP3 players roughly 2 years because of planned ( by
design) obsolescence.

In general the main culprits for old equipment dying are bad caps, wiring
that becomes brittle. Solder joints that become brittle or cold joints over
the years of hot/cold cycles. Traces on circuit boards may also lift with
repeated on/off cycles ( heat) over time.

But the biggest reason for old electronics no longer being around after a
few years is that my wife will get a hold of everything when I am on a
business trip and chuck it all out on garbage day.


"Ashleigh Cope" wrote in message
...
wrote:
Does anyone know how long the circuits/components in old electrical
equipment generally last for? Equipment like, old TVs, radios,
computers, phones, stereos etc - particularly those made int he 1970s
& 80s?
Could they all in theory still work in 100 years time or would their
components/wiring/circuits etc somehow degrade/disintegrate/fail
after
so many decades?
Many thanks in advance for your advice!

who the **** cares. You'll be dead by then anyway.

On Mar 11, 2:47*am, wrote:
Does anyone know how long the circuits/components in old electrical
equipment generally last for? Equipment like, old TVs, radios,
computers, phones, stereos etc - particularly those made int he 1970s
& 80s?
Could they all in theory still work in 100 years time or would their
components/wiring/circuits etc somehow degrade/disintegrate/fail
after
so many decades?
Many thanks in advance for your advice!

old electrolytic and paper capacitors will most likely be duds as they
dry out. construction quality of other components makes a difference;
how tightly metal caps are crimped to carbon resistor elements, for
instance (i have a story...), how well sealed the innards of a
component are against moisture, etc.

then there's the circuit boards themselves, for equipment which has
them. open a military piece of equipment and a consumer piece of
equipment, even an expensive one, and compare.

"professional" stuff can be well built; a few years back i found a
fender guitar amp that had either fallen or been tossed from a vehicle
and buried in a snowbank; a branch had stuck through the speaker cone.
i replaced the speaker and the power switch, whose toggle had been
broken off, and it worked fine ever since. but the quality of circuit
board inside looked milspec.

Claude wrote:
TVs and radios with valves ( tubes) close to for ever but unfortunately
limited to their weakest link, the capacitors. They are good for 35 years
then dry up.

Modern electronics are probably good for 20 if they are of the highest
quality. Computers somewhere around 8 years because of crappy capacitors on
the motherboards. MP3 players roughly 2 years because of planned ( by
design) obsolescence.

Depends on what you mean by 'modern'. I've got solid state equipment
from the era the OP mentions (70's), most of which is working fine. I
have computers older than eight years which also work fine...for what
they're worth.

IME, the main problems with older computers is the onboard battery
backups dying. Caps, except for the infamous problem--largely dealt
with by now--with bootleg electro's a few years ago, have not been that
much of an issue.

It's worthy of note that the Voyager probes have been operating in the
most extreme conditions for over thirty years now. They're expected to
continue working until the 'batteries' go dead, no sooner than 12 years
from now.

http://voyager.jpl.nasa.gov/mission/timeline.html

jak

On Mar 11, 7:10*pm, jakdedert wrote:
Claude wrote:
TVs and radios with valves ( tubes) close to for ever but unfortunately
limited to their weakest link, the capacitors. They are good for 35 years
then dry up.

Modern electronics are probably good for 20 if they are of the highest
quality. Computers somewhere around 8 years because of crappy capacitors on
the motherboards. MP3 players roughly 2 years because of planned ( by
design) obsolescence.

Depends on what you mean by 'modern'. *I've got solid state equipment
from the era the OP mentions (70's), most of which is working fine. *I
have computers older than eight years which also work fine...for what
they're worth.

IME, the main problems with older computers is the onboard battery
backups dying. *Caps, except for the infamous problem--largely dealt
with by now--with bootleg electro's a few years ago, have not been that
much of an issue.

It's worthy of note that the Voyager probes have been operating in the
most extreme conditions for over thirty years now. *They're expected to
continue working until the 'batteries' go dead, no sooner than 12 years
from now.

http://voyager.jpl.nasa.gov/mission/timeline.html

jak

Very many thanks everyone - all your comments have been very helpful.
Additionally can I just ask about how long light emitting diodes last
for? Also processors (cpu chips) on motherboards?
Lastly when did engineers start building electronics with planned
obsolescence - is this a recent thing?
thanks again

Very many thanks everyone - all your comments have been very helpful.
Additionally can I just ask about how long light emitting diodes last
for? Also processors (cpu chips) on motherboards?
Lastly when did engineers start building electronics with planned
obsolescence - is this a recent thing?
thanks again



Most parts like that could last 100 years if not abused, though flash RAM
may lose the data. Use and environment will have a larger effect on life
than anything else.

Planned obsolescence is largely a myth. No engineer that I've met designs
something specifically to fail. Rather they design something to be as cheap
to produce as possible, while still lasting "long enough". This is nothing
new, it's been going on for decades.

On Mar 11, 9:28 pm, "James Sweet" wrote:


Planned obsolescence is largely a myth. No engineer that I've met designs
something specifically to fail. Rather they design something to be as cheap
to produce as possible, while still lasting "long enough". This is nothing
new, it's been going on for decades.

good point, but let's now add the lack of availability of spares and
service documentation to a lot of this stuff. This probably is an even
greater cause of its reduced life!
-B

"b" wrote in message
...
On Mar 11, 9:28 pm, "James Sweet" wrote:


Planned obsolescence is largely a myth. No engineer that I've met designs
something specifically to fail. Rather they design something to be as
cheap
to produce as possible, while still lasting "long enough". This is
nothing
new, it's been going on for decades.

good point, but let's now add the lack of availability of spares and
service documentation to a lot of this stuff. This probably is an even
greater cause of its reduced life!
-B


Again it all comes down to cost. Companies produce what the consumer
demands, and most consumers will not pay a dime more for something that has
parts and service documentation available a few years later than for
something that does not. I would, because I service things and expect them
to last, but to most people, appliances are disposable and are thrown away
when they break.