Electronics blog

  • Agilent 66309D: Repair

    Agilent 66309D: Repair

    A few days ago I got my hands on a faulty Agilent 66309D Mobile Communication DC Source. To be honest, I don’t think I need it, but it was pretty cheap and I was looking for something to either repair or potentially salvage the case of. The Mobile Communication DC Source is a specialized power…

  • Programmable Decade Resistor: Cost

    Programmable Decade Resistor: Cost

    I didn’t really think about the BOM cost of my programmable decade resistor until I was asked. Then I also wanted to know. It is fairly difficult to put a number to what I paid, since I had a lot of components left from other projects that I could use. This includes not only cheap…

  • Quick repair: Logitech M310 mouse button

    Quick repair: Logitech M310 mouse button

    For some time it became more and more difficult to get a click out of the mouse wheel switch of my old Logitech M310 mouse – inconvenient in programs like KiCAD. I also have a newer and “better” M705 mouse, however, using this one seemed to increase fatigue compared with the old M310. The mouse…

  • Programmable Decade Resistor: Panels

    Programmable Decade Resistor: Panels

    I was asked a few times how I did the front and rear panels, so this is what I’d like to talk about in this blog. There are different ways to achieve a similar result. For me, the easiest and most cost-effective solution was to just design another PCB – I know how KiCAD works…

  • Programmable Decade Resistor: Components

    Programmable Decade Resistor: Components

    After being asked about some aspects of the mechanical design and components used a few times, I’d like to address those questions. I have to admit that I’m neither very good at the mechanical design, nor do I have a 3d printer (yet) or a shop where I can do metal work myself. That being…

  • HP 6060B System DC Electronic Load: Adjustment

    HP 6060B System DC Electronic Load: Adjustment

    Currently, the unit’s setpoint accuracy isn’t all that great (readback resolution is limited as well, but shows the offset): Regardless of the range it has an offset of about +20 mA. Sure, for a unit capable of 60 A that seems reasonable, and well within its specs of ±0.1% ±75 mA. But since I’ll use…

  • HP 6060B System DC Electronic Load: Teardown, Service

    HP 6060B System DC Electronic Load: Teardown, Service

    I recently got my hands on a HP 6060B System DC Electronic Load (later also sold as Agilent 6060B). My unit has option 020 installed: Comically large binding posts also on the front panel. This option certainly is not unheard of, but not too common either. Retrofitting is possible, but can be quite some work.…

  • Programmable Decade Resistor: Improved results

    Programmable Decade Resistor: Improved results

    After the modification described in the previous post I let the the “adjustment”/calibration procedure run again. Five days later I repeated the calibration (not the adjustment). As before, all measurements are performed with an Agilent 34401A 6.5 digit multimeter. Accuracy of the resistance First up is a diagram that shows the absolute value of the…

  • About word clocks…

    About word clocks…

    A bit over a decade ago I built a word clock – one of my first microcontroller projects. The project was fairly expensive: It uses a large stainless steel front panel (ca. 39cm x 39cm, laser cut) and a similar sized PCB. Over the years I had to resolder one or two of the RGB…

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