Hi Jimmymac928,
All SS amps have capacitors...i am no techie, but the simple man's understanding is their job is to hold and store energy. How much "capacitance" is a measure of how much energy the amp can store...this helps among other things provide headroom and dynamic capability for when there is a surge or draw on energy due to significant transients in your music.
Over time, capacitors tend to lose their ability to store energy reliably...in a worse case, they leak. Older-tech capacitors had elements that could dry up. In any event, with Krell, which at that generation was largely Class A--meaning the least efficient, hottest burning (but i love the sound best)...capacitors tend to need replacing after 10-15 years. So you 're-cap' them.
Hope that is helpful. A Krell would probably cost about $1000-$1500 to recap...and done well, you should be good to go for another 10 years, as (i am told) most of these well built amps dont have any other areas which would go wrong under normal circumstances...you almost have a 'new amp'.