Could not resist, I found another of those really nice Power Designs power supply on ebay at a really reasonable price. This time it's model 2010 0-20v 1A.
Before cleanup:
After cleanup:
I was expecting the same kind of ovenize voltage reference found in model 2005a, but to my surprise the general construction is a lot more recent and it's equipped with a LM399
look like it's a stripped down version of model 2020.
I only changed 2 caps and did the same operation on the switches with IPA -> Deoxit G5 -> Deoxit S5
And as expected, resolution and accuracy is pretty impressive for a power supply