Opinions of HP/Harrison 6201A power supply?

[JonHendry]

Just picked one up on eBay for $25 + shipping.

https://www.ebay.com/itm/HP-HARRISON-LABORATORIES-MODEL-6201A-DC-POWER-SUPPLY-0-20VDC-0-1-5A/252780150211

0-20VDC, 0-1.5A

Arrived in pretty good shape apart from the decades of gunge inside it. Some of the screws holding on front and end panels don't seem to have much grip on anything.

Powered up okay, except the voltage adjust knob is a bit crusty and when starting to turn the knob from a starting point at maximum CCW, the voltage shot up to maximum when it should have still been in the sub-1V range, then it dropped back down. When I get a chance I'll try to clean the knobs.

Note this isn't the 6102A.