Inexpensive Amp for KEF 107s?

I posted earlier about my (mom's) Nakamichi PA-7 woes. We are looking at getting it repaired. In the meanwhile, I'm interested in hearing of some amps that could adequately power the KEF 107 speakers (which the PA-7 has powered for the past 25 years). Budget is no more than $500.
As always, your suggestions are appreciated.