I would start a new thread specific to the issues you want to resolve for your MC2505.
All the semiconductors are obsolete, out of production for decades and have had multiple substitutions over the years.
Have you bench tested the unit, does it have any specific problems?
There are a number of service bullitens in the Akdatabase for these early transistor units, most often to help the techs, new to semiconductors, get comfortable with them as most of their experiences were with vacuum tubes.