Yeah, if you’ve got one laying around, it makes some sense. Buying a used one that is likely obsolete and impossible to get parts for would not be my advice
Edit: to quote @Beaker , the only one I’ve known to play this trick…
I would not recommend a used Hach unit. The one I have works for the data but the old ones are notoriously finicky. There is a multitude of seperate circuit boards inside as was the design style back then . Power supply boards and the interconnects between boards are with plastic electrical clips on the wire ends that plug the boards together. I worked a career as a control systems design engineer and saw this over and over because I had to design with this kind of component. Over time those connections tend to oxidize and resistance builds. The problem with an oxidized connection is that it is not like either a broken wire or a short circuit and so a voltmeter is very tricky to use to track down problems. Voltages must be read across the connection which most electricians will not understand to do to track this stuff down.
All sorts of glitches creep with oxidized connections and components that will drive you nuts. Error codes will come and go and you have to know where to bang the cabinet and why to make some things boot up lolz. I am certain without an extensive electronics and motion control machine design knowledge a typical user would have returned the unit or trashed it immediately. It has value to me because I have only used it to take single measurements here and there and it is hobby. When I hit the lottery again, or at least if I make it through my disability review, I am looking at a new uv/vis unit.
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