These PSUs are in HP branded 34401As. I think it would be best to replace the lot with Panasonic low ESR units in both DMMs. Much easier than testing each cap. And I usually purchase at least 10 caps of anything I don't have in stock, so the price isn't bad. Both DMMs function normally, so there's no rush.
I keep unused electrolytics for longer than shelf life. Before I use one, I form it with a DC supply. Anyone else do that? Also, when I purchase used DC supplies, I load them, and bring them up in cycles with a Variac (i.e. 0-10V, 0-15v, 0-20V ...., for five minutes per cycle), for the sake of the electrolytics inside, to build the dielectric if the unit might have been sitting for five years. I've got a shelf full of large resistors for the job, up to 1000W. Any wisdom to this practice?
One other question, I talked to a guy in Florida, and he ups the capacitance by one size, because newer caps have different plus/minus tolerances that can make a difference in older equipment. Any thoughts?