Old Aged Components.

Thread Starter

zophas

Joined Jul 16, 2021
111
I have been playing around with electronics for many years and as a result I have collected a large number of components salvaged
from various devices that were cannibalized. The question I have is which components are more susceptible to old age than others? I suspect capacitors would be on the top of the list and I tend to try and use new(ish) ones if possible. I recently bought a kit of metal film 1% resistors and now I can finally toss some of those old resistors that probably came out of old valve radios. Lol. Giving away my age here!
 
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DickCappels

Joined Aug 21, 2008
7,687
Jim Williams (of Linear Technology fame) used to visit electronics surplus stores in the San Francisco Bay Area, searching for the oldest resistors he could find. He said that the oldest ones were the most stable. Don't toss those resistors just yet, especially if they are metal film or wirewound and you anticipate making any precision circuits.

They say electrolytic capacitors don't age well, but I bought out part of the inventory of an automobile tape deck manufacturer in 1989 and among the haul were thousands of aluminum electrolytic capacitors from 2.2 uf to 1000 uf. Even today, every one I pick up is fine. The capacitance may have dropped a few percent, but they work fine.

What I have found to get crummy with age is un-sealed panel mount potentiometers. Cheap ones I bought at an outlet for repair parts for consumer electronics that I bought 20 years ago are now junk because they became very noisy. These are panel mount pots, have not had that problem with trim pots.
 

Yaakov

Joined Jan 27, 2019
3,464
Jim Williams (of Linear Technology fame) used to visit electronics surplus stores in the San Francisco Bay Area, searching for the oldest resistors he could find. He said that the oldest ones were the most stable. Don't toss those resistors just yet, especially if they are metal film or wirewound and you anticipate making any precision circuits.

They say electrolytic capacitors don't age well, but I bought out part of the inventory of an automobile tape deck manufacturer in 1989 and among the haul were thousands of aluminum electrolytic capacitors from 2.2 uf to 1000 uf. Even today, every one I pick up is fine. The capacitance may have dropped a few percent, but they work fine.

What I have found to get crummy with age is un-sealed panel mount potentiometers. Cheap ones I bought at an outlet for repair parts for consumer electronics that I bought 20 years ago are now junk because they became very noisy. These are panel mount pots, have not had that problem with trim pots.
On the caps, heat is the villain, and if they are unused and haven’t suffered a lifetime of heating, they are probably OK (if they were not terribly cheap when they were made).

I have a similar experience with pots. They suffer surface corrosion and sometimes a very good piece of equipments is rendered useless even by reasonably good ones. There are some cleaners/enhancers like Stabilant 22A and Deoxit can do wonders if the problem is on the surface.
 

MrChips

Joined Oct 2, 2009
24,134
You may have ICs and transistors that are stored with the pins stuck in black conductive foam. The black foam that have a dull appearance has carbon particles embedded in the foam. This attracts moisture and will quickly cause the metal leads to corrode after a few years. Discard these black foam and use pink foam or aluminum foil instead.

Store all components in a low humidity environment and use silica gel packets in sealed bags where possible.
 

Thread Starter

zophas

Joined Jul 16, 2021
111
You may have ICs and transistors that are stored with the pins stuck in black conductive foam. The black foam that have a dull appearance has carbon particles embedded in the foam. This attracts moisture and will quickly cause the metal leads to corrode after a few years. Discard these black foam and use pink foam or aluminum foil instead.

Store all components in a low humidity environment and use silica gel packets in sealed bags where possible.
I do indeed have some IC's with the black foam on them. I did not know about the moisture aspect. Thank you. I knew it was a good idea to come out of "lurk mode" on this forum!
 

Thread Starter

zophas

Joined Jul 16, 2021
111
Some things that I have noticed with the old components that I have started playing with, is that they do not solder as readily as new stuff does. I read somewhere that manufactures treat component leads so that they solder easier. Thanks.
 

MrChips

Joined Oct 2, 2009
24,134
The metal on the surface becomes oxidized over time and do not take to solder easily.
Clean the leads by wiping with a piece of emery cloth before soldering.
 

schmitt trigger

Joined Jul 12, 2010
462
In the vintage radio forums there is lots and lots of information about specific components which don’t age correctly.
I would suggest browsing some.
 
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