HP/Harrison 6202B Power Supply

Some time back, I got a bit of an education on Harrison power supplies from the folks on the Antique Radio Forum

IMG 1014.jpg

I was trying to puzzle out the 6202B from the poor scan of the schematic in the manual on the Agilent (now Keysight) web site.

The multiple feedback loops make deciphering the operation of this power supply pretty challenging.

IMG 1004.jpg

The initial problems were that the meter was missing the bezel that holds it to the front panel, ...

IMG 0990.jpg

... the voltage metering was out of calibration, and the current metering just bounced around from meter stop to meter stop as I adjusted the current limit.

IMG 0991.jpg

However, the supply had output and responded to the controls, so it was basically alive.

IMG 0992.jpg

The interior was initially filthy with some kind of oily grime. (These are “after” pictures.)

IMG 1013.jpg

A thorough cleaning with spray cleaner left this residue.

IMG 0993.jpg

I followed it up with a scrubbing by a paintbrush with isopropyl alcohol.

IMG 0994.jpg

After cleaning, everything worked fine!

IMG 1011.jpg

The 6202B is remotely programmable through this row of terminals and jumpers on the back.

IMG 1005.jpg

Fortunately the meter bezel, though cracked, was still rattling around inside the cabinet.

IMG 1008.jpg

So, a little plastic solvent and the bezel was usable again.

IMG 1009.jpg

The bezel slides in from the front of the panel, and then the meter clips into the mounting ears.

IMG 1015.jpg

All back together.

IMG 1016.jpg

I haven’t verified the performance against the specs, but it’s working well enough for my purposes at the moment. It could probably use some new caps.

IMG 1017.jpg

Simon reports that he needed to replace the filter cap on the reference on his 6202B.

IMG 1018.jpg

I don’t have a photo handy, but I rigged up a 10KΩ ten-turn pot to control the voltage via the remote voltage programming terminals. It lets me dial in a precise voltage when I’m using it to calibrate meters against my HP 3468A.

IMG 1019.jpg

I gave it some new feet, since the old ones were torn up.

IMG 1021.jpg


© Steve Byan 2011-2016