Many "broken" electronics have fixes as simple as this. There are a lot of cheap kits on Ali Express to practice solder if its something you'd find interesting. One of the benefits of YouTube is the depth of videos featuring diagnosis and fixing of obscure issues on rare hardware.
I love these power supplies! An awesome feature is the GPIB port on the back (it's basically a parallel port with a specific command set).<p>In college I bought a USB to GPIB adapter on ebay for like $100 and a few cables (you can daisy chain them together) and wrote some VBA macros to automatically sweep the voltage output over a range, and also connected to a frequency generator & oscilloscope to capture the data. My EE labs were done in a fraction of the time compared to my classmates!
For anyone interested in repair of vintage HP instrumentation (among other things) I recommend CuriousMarc on youtube (a good place to start e.g. <a href="https://www.youtube.com/watch?v=CeXYZKg5jdo&list=PL-_93BVApb5_e9h-vqKn1FPUg9WnzFL20" rel="nofollow">https://www.youtube.com/watch?v=CeXYZKg5jdo&list=PL-_93BVApb...</a> )
I had an old home cinema amp with a finicky encoder. The only thing I did was to remove the knob, douse the encoder in contact cleaner and put the knob back. I didn't even open the case. It took a few times to get it back to fully working but in the end, it worked surprisingly well, and it seems to last.<p>Replacing the part is obviously better, but contact cleaner can do wonders if you want to try a cheap and dirty solution.<p>Note: I used the 3-in-1 (WD-40) brand because it is what they have in my local hardware store. I suppose that DeOxit and other brands work just as well if not better.
Can confirm, the knobs on those things are turds. Kinda embarrassing for such an otherwise-nice piece of equipment, too. There clearly are better ways to build rotary encoders, and for a unit with a four-figure MSRP, they could've specified a better encoder!<p>Like the ones Rohde & Schwarz use. I think the detents are magnetic or something; they feel magical.
Sadly not all Agilent/HP equipment uses rotary encoders like this. One of their function generators was brought to me with a clear rotary encoder fault. I opened it up expecting to find a rotary encoder like this. But instead found they had implemented it using circular tracks on the PCB and the knob turned a metal wiper which shorted out the tracks as it turned. After a couple of years of use the tracks start to develop grooves and wear out. There isn't much you can do without replacing the entire front panel which wasn't economic to do. I think within 5 years we binned 15+ of those units.
Old HP/Agilent equipment was beautifully made but in the few years before the sale to Keysight quality took a real dive.
Not directly this machine but you can do fantastic things with old test equipment:
<a href="https://www.youtube.com/watch?v=hdQnpg7b3Vw" rel="nofollow">https://www.youtube.com/watch?v=hdQnpg7b3Vw</a>
<a href="https://www.youtube.com/watch?v=MfH53a9xAjo" rel="nofollow">https://www.youtube.com/watch?v=MfH53a9xAjo</a>
I'm curious to see what the inside of the rotary encoder looks like; I've revived a few of those by just cleaning and relubricating them, if the contacts haven't completely worn away.
If you tinker with electronics, buy a dc power supply.<p>I've been meaning to buy one for years, and only bought one recently at an estate sale for 30 buck.<p>It's just so convienant having the right voltage for testing, and repair.