Don't bother buying a manual, head to Tekwiki where I've uploaded everything I can find for these scopes.
You'll only need to replace the VCO board if the two capacitors on the board have leaked a lot and damaged it. I have done one replacement, but other scopes didn't have enough leakage to need it. A visual inspection is enough, if you see corrosion of the traces, it's a small board so better safe than sorry IMO.
I leave the boards in to dry from the heater in the dishwasher, then blow out any remaining water from under the chips etc with canned air or an air compressor with the pressure turned down to avoid parts flying off the board.
Give it a few days and a blast with a hairdryer to be safe and you'll be fine.
Don't put the input hybrids through the dishwasher though! They are delicate and never need it anyway.
Jared
Jared Cabot