I disagree with your assessment about charging more if you have them repaired. You still have an amplifier that is pushing 30 years old (think of it as rebuilding an engine on a 30 year-old car -- the transmission can go next, followed by...).
The market value for a working KSA 250 is about two thousand as others stated above, regardless of what you put into it.
The market value for a working KSA 250 is about two thousand as others stated above, regardless of what you put into it.