Heh we have those multimeters at leeds hackspace . . . they don't last very long, do they?

I pride myself on being a practical type, so when I'm out and about visiting relatives or friends, it's inevitable they will ask me to look at something (electronic or otherwise). I've been asked to debug soy milk makers, washing machines, treadmills, computers, radios, telephones, ADSL modems/routers, light switches, power points, LCD TVs, monitors, etc. Half the time, if it's not urgent and it's small enough, I'd shove it into my bag and take it home so I can use the stack of tools and test equipment I have at home to diagnose and repair the issue. But that's not exactly practical when you have a 55" LCD TV that needs a fix!

It's also not practical when your work involves a lot of travelling and demonstrating prototype devices on site. A local news film crew was invited to see a prototype device we had built in a live demo situation. Everyone knows that live demos always go to plan and this one was no exception. Ten minutes before the crew arrived, the equipment began to malfunction causing erratic data values to be recorded. We suspected something may have gone wrong with the battery - but replacing this did us no good. Then we suspected it may have been radio interference, but taking it off site didn't fix the issue. I felt a rising lump in my throat - this could have been a disaster for me and could have cost me my job, as we thought that perhaps there is a firmware bug and we'd have to resort to a less impressive Plan B (i.e. a pre-recorded demo, which I had also prepared).

With some quick thinking, I grabbed the only tool I had - a screwdriver I bought from home. I opened the device and gave the PCB a bit of a push while powering up - the unit came on normally and was working again. Hastily reassembling the unit prior to the crew's arrival, I told my superior (who would be on-screen) not to turn off the unit or it may fail. The filming proceeded relatively smoothly, until half-way during the shoot, the unit was powered off. Not wanting to cause a scene, I jumped in and toggled the power switch a few times to no avail. I eventually placed it on a chair and sat on it, while powering up, and it was back to life. Filming was completed uneventfully.

Afterwards, the unit was taken up to our labs where an investigation revealed that some unrouted traces that had been "green wired" using kynar wire had some cold solder joints which led to the ADC not initialising with the correct parameters. If only we had something on site to work out the bug - we wouldn't have spent so much time changing batteries, taking the unit off site and may have just taken it up to my office where I could have touched up the joints! At least I still have a job ...

- Gough

I love participating in various science fares and other student competitions.

I also go to several maker gatherings here in India.

I was the youngest (<18) year old participant in the robotics area of MakerFaire Bay Area this year.

I don't have an oscilloscope so a small USB would be really great. Also in those fares I don't have a lot of space so an USB oscilloscope is great.

Also, in such times debugging quickly is very essential when you are confused, so the tools would really help me.

A long time ago I had tried to make a simple oscilloscope circuit from the internet that can measure say a sine wave but that never worked so a Oscilloscope of any form will help me understand electronics in a better way.

Also I need some professional measuring tools because currently I am using a $2 AliExpress Multimeter and a normal scale which don't turn out to be very useful.

There have been many many times when I've been visiting a friend or relative and they say "While you're here, can you take a look at this - it's not working".  Of course I have no tools with me, and all they have is a hammer and a giant flat end screwdriver you could chisel rocks with.  You would think that having duct tape on hand would be like having milk and bread these days.

On our MISO-BOB field experiment in the Indian Ocean this year, I was on a ship for 30 days and had to pack every tool I could think of needing, and we still had to borrow stuff from the ship stores.

The worst thing to try and fabricate on a ship is a high density connector for an instrument that you forgot to pack the interface cable to.

Scott

14rhb  wrote:

 

... if the wiring behind a fitting or socket ever looks slightly non-standard I snap a few photos on my mobile, just in case.

I tend to do that now even where things are relatively standard, just so I can double check my own work. Took me a while too, to remember to do that.

I tend to run into interesting scenarios when visiting my father in law, when it comes to electrical things and often more specifically with electrical things in boats.

One time they asked me over to help replace the electric hot water tank. He had turned off the breakers. Wait, I should be using airquotes: "turned off the breakers"... but "for some reason" it gave off a massive spark when he touched the wires to something!  yikes... so yes he turned off some random other breaker. If I recall correctly, there was a '1' missing, so instead of 14/15 it said something like 4/15. In any case, I have a no-contact line voltage tester and we quickly found the correct breakers to turn off and replace the tank so he could get into hot water in a much better way

The boat... sigh, yes the boat... there's always something rusting when dealing with salt water near electronics. My wife and her dad go fishing a lot, so they own a little boat together. And I guess the maintenance of the electrics have become my job haha

And my father in law has tools that must have been inherited up through the generations from the early 1800s... "I have a wire with a light for testing!"... thankfully I do generally remember to bring my trusty digital multimeter for these sorts of things. "Go short out something else somewhere else!" In one case he did actually end up shorting out power to ground and ended up with a 12 foot long hot wire through the boat, melting some seat vinyl along the way - yikes! Let's buy a fire extinguisher for the boat, ok?

One little tool thing he uses is a little 12v light he uses to probe with. I find it's not very reliable though, as in one case he concluded there was no power on certain circuits and he was about to tear out and replace all sorts of expensive parts of the boat, but then when I tested with the DMM I noticed it was fine on the battery side, but somehow reduced down to about 7 volts on the other side of the fuses - turned out the corrosion in the fuse box was causing too much resistance. Cleaning all of fuse holders and the fuses carefully with some fine sandpaper restored full power to the bilge pumps, marine lights, wipers... all those little details that might come in handy while out on the water   (bilge pumps plural... there's a nearly-sinking story that goes along with that, of course)

The funny thing is he usually tries to push his old tools into my hands when I go to check things, because he "doesn't trust" those fancy multimeters I use

(So yes, I often secretly check things when he's not there haha!)

Cheers,

-Nico

I never seem to remember I can do that. Great idea!

I had foolishly removed the two, three way light switches at either end of the hallway without documenting the connections.

You are not alone on that one - now if the wiring behind a fitting or socket ever looks slightly non-standard I snap a few photos on my mobile, just in case.

In the summer of 2019 I was visiting my 83 year old Aunt in her 100 year old home. Home improvement shows had convinced her that white light switches and plugs were more ecstatically pleasing. A change was needed.

With a combination total of over 80 plugs and switches, I set a day aside to make the renewal she decided was necessary. I had returned to my Island home of Newfoundland for a summer vacation. Oops, I am told the word vacation is not contained in a retired person lexicon. I returned home for some summer fishing. Staying with my Aunt was one of the joys.

With a 3.5lbs, Atlantic salmon caught that morning during a 6 a.m. fishing excursion, I made a foraging trip to the hardware store for the needed wiring supplies.

Let’s cut to the chase in the story. I had foolishly removed the two, three way light switches at either end of the hallway without documenting the connections. Before installing the replacement switches, I was called for lunch of fried salmon.

The existing wires had been connected to flat Bakelite switches made I assume, sometime during the 40's or 50’s. The wires in the boxes were short. Before lunch I had pulled all the wires straight to regain some length in order to position the new switches.

Installing three way switches is not difficult if three conductor colour coded wire is used. In my case only two conductor wire was used. Some of the conductors had paper insulation, with no distinguishing color between the wires. Others were just black or white. To add to the complexity, there were two different lights, at opposite ends of the hallway, controlled from the two switch arrangement.

I could have really used the MP730026 EU-UK -  DIGITAL MULTIMETER, TRUE RMS, 20A, 1KV to assist me in installing the new switches. It took me close to three hours to figure out the wire combination to hook to the switches to get the replacements working. I contemplated during one internet search of heading to the local Radio Shack (now called something else) to purchase an inexpensive VOM. I blame the smell of fresh fish cooking as the distraction that made me forget to make a circuit drawing. How hard can wiring up a switch be? If all the wires are of a similar colour, it is difficult to say the least.