Well you can only be sure if you measure them especially the ESR.
Actually mine were all 0,00 when I measured them individually.
The KSA-250 I think you're referring to, is even a few years younger as my KRS-100's (1989) and changing the 6 large cans is pretty expensive and I have 12 of them...
I changed the 48 orange axial Roedersteins (470uF, 100v) and they still measured good with low ESR and more capacitance than specified (around 600uF all of them). But they were from West-Germany implying at least 30 years old so now I do not have to worry about them anymore.
Actually mine were all 0,00 when I measured them individually.
The KSA-250 I think you're referring to, is even a few years younger as my KRS-100's (1989) and changing the 6 large cans is pretty expensive and I have 12 of them...
I changed the 48 orange axial Roedersteins (470uF, 100v) and they still measured good with low ESR and more capacitance than specified (around 600uF all of them). But they were from West-Germany implying at least 30 years old so now I do not have to worry about them anymore.