Agilent

The HP/Agilent 6632B is a remarkable power supply. There are some similarities with the mobile communication DC source 66309D I “repaired” recently: The 6632B is optimized for a fast transient response and it has a low current range too. But the circuit and its properties differ significantly. One important aspect: Where the 66309D only has a downprogrammer that doesn’t track the current setpoint, the 6632B goes all-in: It’s a two-quadrant power supply - able to source and sink current over the full operating range from 0-20V at 0-5A in CV and CC mode. ...

Many older HP/Agilent instrument share a similar feet design. There are at least two different types though: One with a metal part to prop up the instrument and one without it that can be used on all four corners. The feet can be detached from the instrument, e. g. for use in 19" racks. This also means they got thrown away too often, so that many used instruments come without them. For some time they were available on ebay at a reasonable price. ...

The other day I noticed an issue with one of my Agilent 34401A’s: I measured a constant DC voltage and after a few minutes the measured value would start dropping and become unstable. Then I got curious and checked the two-wire resistance mode. Same story, maybe worse. A word of caution: High voltages found inside the DMM can cause damage, severe injury or death. If you are not authorized or qualified to work on such devices, don’t do it. I don’t take any responsibility for actions you take or the results of these actions. You do everything at your own risk. ...