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

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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.

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

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... 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.

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

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

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A thorough cleaning with spray cleaner left this residue.

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

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After cleaning, everything worked fine!

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

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

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

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

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All back together.

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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.

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

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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.

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

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© Steve Byan 2011-2019