Ok, I've had a quick look through the manual and all the voltage rails are interlinked with each other and the main one that everything references is the 18v so that has to be 100% healthy before the others can function correctly so if the regulators and the transistors are readily available I think I'd be inclined to replace them all without exception and also the caps on A1 card, the PSU. The diodes all checked out as OK and the resistors so then you will have effectively, a refurbished PSU card.
Next I'd run the meter with the bare minimum card set up, which as going to be the following cards installed, A1, A2, A8, A9, A10, A11, A12 and A13 and see what happens both to the voltage rails, ripple and display, then I'd follow the chart on pages 4.16 and 4.17.
Section 6 deals with the option cards and suggests items to check if checks run on them fail so it looks to be a good manual, just need to be patient and read it through and follow logical steps before moving on to new things.