Hi!

any idea as what to check on these units?

Which particular G4 do you have? There are a few different supplies in
use, some across more than one model.

They seem to be pretty good quality, I have some that have run around
the clock for pretty much the past eight years.

i assume recap or at least look/smell around for
burnt electrolytics...

I would definitely check that. When working with even a moderate load,
these supplies run warm and don't move much air through the casing.

William