stevem Messages: 4743 Registered: June 2004 Location: NY
Senior Member
There's no way to tell unfortunately.
These types of caps last way way longer when the amp is atleast power on for 30 minutes every few months, like every 2 to 3 months.
The two big can type main power rail filters that where of the computer grade types seem to last forever , and many times can be re-formed .
In a 1980s amp they may have gone away from the great filter caps I just posted about and gone over to the toosie roll type, and if that's the case then by now ( ( 40 plus years ) if nothing else those two main power rail filters should get replaced just for starters.