How to Annoy Your Friendly Neighborhood Electrical Engineer

Problem Statement: A power assist chair (that we purchased for my mother back in 2016 and no longer need, looking to sell used) had an intermittent – the up/down LED lamps would go out, and the chair would not operate, until one jiggled the power cord.

Annoyance #1: Called the manufacturer to get a replacement cord (I had troubleshot it down the cord itself). Turns out the cord is hard-wired into the motor, so the solution is to replace the motor. (bad answer, the motor itself is fine). Why is a simple power cord that will invariably get a bit of wear and tear not be easily replaceable?

Annoyance #2: Yes, it’s under warranty, but it requires both a service call (to replace the motor) and shipping charges. Um, no.

Annoyance #3: Additionally troubleshot the cable and discovered the intermittent was in a little inline molded box containing an LED, the sole purpose of which (as far as I can see) is as a redundant and unnecessary troubleshooting tool – since both the chair control pendant and the transformer also have LEDs to indicate power on.

Solution: Cut the molded box LED out, strip and splice the cable (nicely soldered and insulated), it’s a wee bit kludgy with electrical tape, but perfectly safe and solid). Took about 15 minutes including time to heat up the soldering iron and then test the crap out of it afterwards.

Ultracomfort America – not impressed.

Audio Project: Buying Local vs. Amazon

I’m in the middle of a small audio project – converting 11 digital micro-cassettes (the sort used in old answering machines and personal recorders) to digital MP3 files for a client’s book / memoir project. It’s potentially slogging work (each cassette has up to 90 minutes of content, that’s up to 16.5 hours of recording) but I’ve got it set up to run in the background, while I do other things. I’m sort of embarrassed to admit that I started doing this on my computer (using Audacity sound recorder / editor) before realizing I have this perfectly good TASCAM DR-07 digital recorder (that I use for live recording) that is actually designed for this sort of thing. Using the computer would have been exceptionally onerous; the digital recorder makes it almost trivial. The only potential problem is battery life on the micro-cassette – I picked up a DC power supply but it introduced severe hum into the signal so I’m back to AAA batteries (I have a stack of those, but I imagine that the batteries will die mid-recording a few times during the process.

I’m probably over-killing the set-up here – running the 2.5mm mono output of the recorder through adapters (2.3mm -> 3.5mm -> 1/4″), then through a DI to get XLR out, and into a Mackie mixer to tweak the sound a bit (cutting out some of the highs and lows, optimizing the level) and into the recorder. I’ve got a set of headphones to listen in now and then. Next time I’m out I’m going to pick up my spare monitor speakers at my storage locker so I can have it going low in the background and lose the headphones.

Getting the adapters was 1/2 the battle here – the 2.5mm mono out is super non-standard. I went to the local Cables & Connectors store which could only supply a 2.5mm stereo, which kind of sort of worked but not really (was a little flaky) – I ended up (as always) finding exactly what I needed at Amazon (2.5mm mono to 3.5mm stereo) and while I was at it, picked up a couple of 3.5mm stereo to 1/4″ breakout cables which I seem to be wanting every other time I pull out the mixer these days (record out to the TASCAM, line out from phones and tablets). I have a bunch of 3.5mm to RCA breakouts but the 1/4 is a lot more mixer friendly.

I like to support local retail when I can, but I’m invariably looking for something a little weird or left of center and rather than drive around all day for something that almost works, just pull up the exact right item on Amazon, order via Prime, and it shows up 1-2 days later. Probably better for the environment as well (considering my gas).

White Paper: Power Strip Safety and Regulatory Compliance

Came across this courtesy of the folks at 24×7 Magazine and Tripp-lite Corporation

Power Strip Safety and Regulatory Compliance:
A Comprehensive Guide to Utilizing Power Strips in Healthcare Facilities

Executive Summary
As the use of power strips in hospitals has become more widespread, their misapplication has also become increasingly prevalent. Incorrect use of power strips in healthcare facilities can result in citations, fines, or even patient injuries. This White Paper discusses the common mistakes made in using power strips in healthcare applications and introduces a methodology to promote safety and compliance. Moreover, this White Paper examines the most current codes and standards governing power strips in healthcare applications and the ways those codes and standards may impact your healthcare facility.

Download Here

Going Someplace Exotic?

World Electric Power Guide:

Electric Current Abroad: (U.S. Department of Commerce)

Precipitated by a colleague looking for the voltage he can expect in Japan. (The answer: 100/200 VAC Single Phase, 200 VAC Delta)

Did you know that 1/2 of Japan is 50 Hz (East) and 1/2 of Japan is 60 Hz (West)? (There is a dividing line running North-South through Shizuoka on Honshu Island.

Two thoughts: if one is traveling to Shizuoka, be ready for anything. And although this seems totally insane, one can imagine that early Japanese products, designed to work for both 50 and 60 Hz in the days before modular power supplies and universal inputs, would have been a lot more competitive on the world market than products designed initially for either 50 Hz or 60Hz, but not both.

Another good resource for world voltages (if you actually want to pay for a small booklet, which I did many moons ago) is British Standards Institute document TH 20338: World Electricity Supplies – Voltages and frequencies (£65.00) which you can purchase online here.