While the capacitors still look ok, I cannot tell if they indeed are.
From the 1980s? It's safe to assume they aren't.
Why?
There is no real wear-out mechanisim for plastic film capacitors of this era. Apart from manufacturing defects or overloading there is no resaon for these to fail. Even the stacked plate ones that were sawn up and not encapsulaed don't seem to fail.
People seem to think that because Rifa sealf-healing caps and some electrolytics are known to fail that all capacitors will die.
The quality wound plastic film capacitors only real faiure is when they have been subjected to excessive voltage, dV/dt or current. These are unlikely in a crossover.
Don't tar all capacitors with th Rifa brush.
The problem is they are often difficult to identify; metallized paper axials look very similar, and confusion there adds to the body of evidence that all capacitors are suspect above a certain age. Add to that the fact that we don't know the exact chemistry of the plastics involved in those "old" plastic film caps, and there can be some properly placed misgivings about whether those plastics have begun to break down with age over the course of decades.
The problem with caps in general is that there is a fair measure of voodoo in their construction and application to the average electronics nerd; even engineers can be ignorant of things like how electrically fragile tantalum caps can be or how critical is the difference in derating curve for MMLCCs vs other types, how ESR vs ripple rejection ratings apply in a brute force filter, and how different kinds of caps in parallel can interact on a power rail vs signal path.
I'm certain there are easily a dozen other critical considerations as well that I'm just not thinking of;
I'm still right about here on my first cuppa.
Bottom line is Tesla's ghost lives in each and every one of them; plus he's pissed off and a little bit crazy. You NEVER know when SOMETHING is gonna drive one over the edge. ![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif)
mnem
MAXIM # 9. Capacitors are Murphy's Footsoldiers.