Safety of Older Electronics

Some electronics never die. They just get moved to secondary, tertiary, etc. systems. In my case, I have two old receivers connected to televisions. I'm guessing one is 25 and the other 30 years old. The remote sensors are on all the time and occasionally one forgets to turn the receivers off. They can be replaced with relatively inexpensive amplifiers for how they're used, but I thought if it ain't broke don't fix it. At least until recently when I've started to wonder if continuing to use them is a smart idea even though there is nothing apparently wrong with them. I'm thinking in terms of a damaging (catastrophic?) failure particularly when the receiver is unattended. I'd appreciate input whether one should continue to use older equipment that can be inexpensively replaced.
I am running a Pioneer SX 737 receiver (circa 1976) while in temp housing and I leave it on all the time. I need to install the replacement relay so that I can turn it off and on without banging and clanging but I am not worried about it electrically. It is plugged into a PS Audio Premier Power Plant so I trust it will be shut down if the sparks start to fly. If I have enough advance notice I'll be sure to invite ya'll over for the weeny roast.
Our lives are also irreplaceable....keep listenning and not worrying...
Had a Sherwood receiver (1972). Thought everything was ok with it till I left it on one morning when I went to sleep after my night shift at work. The unit went into some weird oscillation mode emitting what I would consider some sort of damaging sine waves. It took out the woofers in my vintage Advent speakers. Literally twisting the voice coils in their gaps, totally destroying them. Its a good idea to have a receiver like this refurbished with critical caps and resistors replaced not to mention a complete inspection of the innards. There is a gentleman down in Texas who does this sort of work. Can't remember his name but I think his company is called Circle Audio, I think.
One thing that can fail are electrolytic caps.

Have them repleced and all should be good. It will probably sound better afterwards.

You might find the odd high power resistor fails also.

Every thing else should be fine.

A good tech should be able to assist for a reasonable price.

Vintage solid state electronics that haven't been shelved
or garaged, used regularly will last longer than ones
unused. Transistor life is endless it spans up to 60,000
hours if USED regularly which is approximately a lifetime
or longer. As to DC filter caps is basically same. They
go bad if not used.
Yes, filter caps go bad when gear is not used for a very long time because electrolyte "eats" out aluminium oxide, a dielectric, reducing breakdown voltage (presence of voltage slowly rebuilds it), but filter caps can also go bad because they simply dry out. Current heats up dry capacitor because of its increased ESR causing further increase of ESR with temperature, resulting in avalanche effect and explosion of the capacitor. Because of that electrolytic caps have either fuse (rubber plug) or weakened top (groves). In room temperature capacitor will last 40-50 years but every 10degC temperature increase cuts its life by two. Capacitors placed in hot areas, for instance close to tubes, won't last very long.
Replaced that relay in the SX 737. All went well and no more banging sounds just nice clicks. And it sounds better too.
Thanks for an interesting thread, also for a non-engineer.
Kijanki, the 10degC rule, what is the starting point, the “normal” temperature in the box? I have ca 20degC in my listening room, but the temperature inside the audio boxes varies from very hot esp tubed equipment, to medium hot to quite cold just a bit above 20degC. If the rule is true – hot-running boxes should be serviced quite often! Is there a typical failure time for electrolytic caps (Williewonka) for each given temperature in the box? Also, I did not know about the use factor, that it works positively over time (Czarivey).
Since the thread concerns how to minimize wear and tear and aging, it is of general interest, not just for vintage owners. I started a “total cost of ownership” thread some while ago here on Audiogon, check it up – this relates to the same theme.
So ideally, the user could check the temperature within the box, input yearly “on” time (or total use hours), and know when it is time for service, and what components should be replaced?
O_holter, if you work daily or working out, you will feel substantially different than if you're daily watching TV and sitting in front of PC.
It speaks for itself.
Sorry what do you mean?
I got it...I agree, I knew about the rule that it needs to be turned on, and do work, in periods - and not left stone cold. This is in tune with my own experience over the years - it is after longer periods of being off, that mid-age equipment is likely to fail. Having not being used for a longer period.
Me too. I'm in mid-40's and can't cope with loss of energy. My "mid-aged equipment" must be used daily otherwise -- age, doctors, RX really really sucks and costs lots of money...
Gotta run to play some volleyball after sitting in office. I always go after the wise phrase of Kirk Duglas -- "The life stops when you stop living". It's nice here in North Carolina and every chance to be outdoors is mine.
Yes. We have some of that in Scandinavia too, great outdoors where I live, big woods north of Oslo, I go there to charge my batteries, so to speak.
O_holter, romm temperature is around 20degC. It is hard to tell what is lifespan of the cap since different companies put different numbers. I would assume >50 years in 20degC. Capacitor will fail only if you leave it unpowered for many years. Cold capacitor has lower ESR.
Yes I realize. It can be tested but a lot of work. My experience as a user is that the hotter the box, the greater the need for regular service. Although I have had some great exceptions too. The Krell FPB600 amp ran very hot, in periods, when I played loud music, over twelve years use, and never showed any sign of failure.

So, if it is difficult to make a general rule, service after five, ten or fifteen years, based on temperature in the chassis - perhaps a better way to go, is through the symptoms of aging equipment? What are the typical signs of caps and other parts that are no longer performing optimal?
Dry power supply caps have high ESR (Equivalent Series Resistance). First symptom is loss of bass tightness/dynamics. I've seen (in commercial equipment) cap that was bulging (placed next to hot transformer).
Thanks, very useful. Other symptoms to look for?

Czarivey, I have experience with old amps that confirms the rule, dont leave them off for years, that you mentioned above. Like my Revox A78 amp. It always played decent in the 1970s, was left off for ten years after being replaced by a Yamaha amp in 1985, but when I brought it to a friend's cottage, to try out among other amps, fifteen years later, it just did not sound at all, the music was clearly wrong-sounding. So I had to pack it away, a bit embarassed. The Yamaha amp, on the other hand, having been used off and on for fifteen years, required service in the late 90s, but the loss of optimal sound was much more graceful, not catastrophic as in the Revox case.