Levinson 20.5 monos - Time for a Refurb?

I bought my Mark Levinson 20.5 pure class A mono blocks new in 1990. I loved them for their sound and still do. They have been 100% reliable and I have never had them back to the Levinson or my dealer for anything.

However, they are 16 years old now and except for my Magnum Dynalab tuner, they are the only thing I have not replaced in my system.

Being pure class A amps they run pretty hot.

Question is, is it time I should consider having them checked out, refurbished, capacitors and the like replaced, etc?

If so, who should I consider for this work? Levinson? They are not what they used to be when they designed and made these amps, and I'm not sure they are up to the same quality work they did back then or whether I should trust that their parts will be as good as the original. Someone else? But who?

Has anyone been through this or does anyone have any thoughts about this they can share with me?