Electronics – Ursecta

A very disinfected stethoscope

A couple of years ago I bought a Littmann 3200 electronic stethoscope. Love the thing. Fantastic (and adjustable) sound and recording capability and Bluetooth connection to upload those sounds to a companion app.

A couple of weeks back, the stethoscope started to glitch. Every now and then it would hard reset when I pressed the “-” button so I thought that was the end of it. I ordered a new one, planning on disassembling the old one once I had another good one. Today was that day.

Fluke, old and new

I’ve talked about my old Fluke 77 DMM before, but now I can compare it to my “spanking new”¹ Fluke 289 DMM. This thing has it all: a lot of accuracy and precision, features galore, logging, and otherwise nice specs. I got the package with the PC software, data cable, and the Bluetooth/IR connector for the phone app. Continue reading “Fluke, old and new”

ESR

In the previous post I described another failure in my Razer Mako speaker system. I found a defective electrolyte capacitor and I said it started to “short out”, which isn’t correct. What happens is almost the opposite, namely that the internal resistance in the capacitor starts to rise, creating heat dissipation (which almost burned me) which ultimately destroys the capacitor. Meanwhile, before it actually gets destroyed, it becomes less efficient at doing its job of smoothing out variations in the voltage applied to it, which I saw as increased ripple on the corresponding power line.

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Razer Mako (no click of) death fix

About two and a half years ago, I wrote a post about fixing the “click of death” problem the Razer Mako 2.1 THX speaker system is prone to. My Mako worked fine until recently when it failed in another way, namely with no sound at all anymore. No clicks, nothing. While the “control puck” still kinda worked, it flickered and behaved weirdly.

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The benefit of quality

35 years ago, I bought a Fluke 77 multimeter (series I), which was pretty expensive by the standards of the day. I’ve used it with moderate intensity since then, changing the battery every couple of years, but not having it repaired or calibrated. I never had anything to calibrate it against, anyway.

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