Our Biggest Screw-Ups

Thread Starter

djsfantasi

Joined Apr 11, 2010
6,792
In another thread, a member admits that his issue was simply due to shooting oneself in the foot In other words, an "Oops".
Ok, this is now really embarrassing.

The manufacturer called and we figured it out. The LED light needs a 24 V power supply and I grabbed one with 12 V. With other words, the LED light is not fried at all, the 12 V just didn't cut it. Just hooked up the matching supply and all is working.

I mixed up the power supplies, because the aquarium filter uses the same 24 V power supplied and that's where the LED supply ended up being, and the 12 V must be from the skimmer or something.

I'll mark all power supplies from now on! I guess I'm getting old. :(

What a joke.

Thank you Dennis for looking into this, I really appreciate it. I'll be back soon with my next screw-up. lol
I started this thread to demonstrate to noobies that we all make an "Oops" at one time or another.

I was making an animatronic, with a custom servo driver board. It tested fine on the bench, but went wacky when I installed it in the animatronic. People here made several good suggestion, but they didn't solve the problem. Cut to the end of the story.

When installing the board, I accidentally flipped the connections. The pin connections on the board was an identical row of servo headers, so it was easy to flip.

Was certainly a forehead slapper.
 

strantor

Joined Oct 3, 2010
5,329
I haven't the slightest notion what you're talking about.
</sarcasm>
Mod edit: Removed questionable image. JinTX
 
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RichardO

Joined May 4, 2013
2,271
"Biggest" screwup? That is a hard one to call. Here is one of my better examples.

I had an in circuit emulator connected to a microcontroller project. Things were not working so I kept changing the hookup to fix the problem. I was having a very bad day and everything I did made the problem worse. The final straw was when I managed to apply 13 volts to the 5 volt circuit. That took out the $50 emulator chip -- which was quite costly at the time.


I just remembered another one.
I was working on the design of a unit that needed to be protected by a fuse for safety reasons. I originally specified too high a fuse value. This was pointed out by my contact at Underwriter Labs. (UL). I was confused so I replied back accordingly. The UL person gave me more information on what I did wrong. I was still confused. This went on for a few cycles. When I finally got my head unwedged it was now obvious that I had been given good information from the beginning. What made the difference was when I actually read the information I was given instead of just glancing at it thinking I already knew what it said.

Fortunately everyone involved both -- my customer and the UL person -- were very diplomatic.
 

dl324

Joined Mar 30, 2015
11,485
Learned a new word. Thanks for that.

I was lucky that even though my Wife and I lived on a single income, I put 20% of my income towards retirement for the last two decades of my career; instead of always having a new car, taking big vacations, and buying more house than I could afford.

That gave me more options when I was injured in an auto accident and had to retire prematurely.
 

MrChips

Joined Oct 2, 2009
21,827
One of my biggest electronic screw-ups was I laid out a PCB for a VIC20 expansion board and all my eight data lines were flipped, D0 to D7. I had to cut traces add jumpers. What was supposed to be the production board ended up being the proto board.
 

#12

Joined Nov 30, 2010
18,210
I replaced a fan motor about 200 feet from salt water. Naturally, the shaft was so corroded that I couldn't get the fan blade off. I put axle grease on the new motor shaft to suppress corrosion. Three months later, the fan blade walked off the shaft and frisbee'd into the Freon coils.

The moral of the story is: Never let a lubricant get near a set screw.
 

wayneh

Joined Sep 9, 2010
16,399
I can think of two events, both when I was a kid. One was putting tweezers into a wall socket. Yeah, I really did it. I remember a blinding flash and yelling from the next room after the breaker blew.

The second event was touching something inside my brother's ham radio power supply. It had a tube inside that glowed green on top and I was fascinated by it. Touching something in there made me jump several feet back and land on a the bed. I laid there staring at the ceiling for minute or two until I was convinced I was probably still alive.
 

strantor

Joined Oct 3, 2010
5,329
I bought a Prius when gas was expensive and sold it when gas was cheap. Financed at a high rate for 2 years. Total of 24 monthly payment minus price I sold it for, I would have paid as much to rent it from Hertz for 2 years.
 

killivolt

Joined Jan 10, 2010
786
Working on a customers dishwasher, I already figured it was a bad water valve from the call so I carried one in with the tools to replace it, my pocket volt Meter got broke and I didn't carry any more than the valve and replacement tools. I opened the door handle thus disabling the power or so I thought. I turned off the water supply and grabbed the pipe in one hand then reached and pinched the wire spade and Whamo........ next thing I remember was wakeing up on the floor limp like a noodle couldn't move for about 1/2 hr.

Thing is no one was home, I thought to myself I could have been dead on the floor when the customer came home, what a picture that would have been.

kv

Edit: When the dishwasher was installed they reversed polarity.
 
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AlbertHall

Joined Jun 4, 2014
10,388
When I was a lad I had a TV (valve, live chassis) and I was modifying the tuner of another TV to be an aerial preamplifier. I had connected two wires with croc clips on the ends in series with the bottom of the heater chain to power the heaters in the extra tuner and had the clips clipped together and was watching the TV. I had made sure that the chassis was connected to the neutral and so safe to touch (sort of). I was ready to power up the preamp and decided to just connect the heaters first to make sure they worked correctly. With the TV still switched on I picked the two clips and separated them. Big oops!
I now had one hand holding a clip on the mains neutral and my other hand holding a clip connected by the heater chain (about 800Ω, 300mA heaters) to live mains. I couldn't release the clips, I couldn't switch the TV off, I couldn't shout, or indeed make any noise. Eventually I realised that my legs still worked and if I just walked away something would give and indeed it did.
I am really quite surprised I survived that one.
 

ErnieM

Joined Apr 24, 2011
8,055
Back when I was a kid my father used some very old connectors to wire up a speaker. I matched this connector to one on an old tube radio. Thinking this was another speaker outlet I plugged A into B. Discovered the connector was actually an AC port and the speaker made a VERY LOUD SOUND until it self destructed seconds later.

Oops.

That wasn't my biggest mistake by a long shot.
 

cmartinez

Joined Jan 17, 2007
7,081
Mine happened about 12 years ago, when I was working with my first oscilloscope. It was a cheap Hantek USB 100 Mhz with two channels.
I was measuring the readings on a 120VAC line using my laptop, and thought it a good idea to attach the 100x probe's ground clip to the neutral wire. And it worked at first... until I got confused and attached the clip to the live wire instead... As would be easy to guess, lots of shiny colored sparks, fireworks and magic smoke were produced...

The amazing thing is that only one of the scope's two channels was burnt... and only the USB port in my computer to which the scope was connected stopped working... I was very, VERY lucky... and thoroughly learned my lesson, of course
 

nsaspook

Joined Aug 27, 2009
7,587
Not the biggest unless someone else notices, two 'random' patterns next to each other on the rotten floor repair and Porcelain tile job.:oops:

 

nsaspook

Joined Aug 27, 2009
7,587
o_O ... c'mon... that the best you can do? Surely you have much bigger sins.. :D
Unless I put a small rug there I will see that 'sin' everyday while making coffee. :eek: The big sins happen once and while traumatic at the time have faded into 'sea story' land.
My (and my fellow workers in the room) greatest Screw-Up with electronics almost got a person killed and caused great bodily damage to a co-worker. It involved high voltage DC, high voltage RF and hallucinogenic drugs from the golden triangle. The only thing good about the incident was the person injured didn't feel any pain when the shock happened.
 

cmartinez

Joined Jan 17, 2007
7,081
Unless I put a small rug there I will see that 'sin' everyday while making coffee. :eek: The big sins happen once and while traumatic at the time have faded into 'sea story' land.
My (and my fellow workers in the room) greatest Screw-Up with electronics almost got a person killed and caused great bodily damage to a co-worker. It involved high voltage DC, high voltage RF and hallucinogenic drugs from the golden triangle. The only thing good about the incident was the person injured didn't feel any pain when the shock happened.
:eek: And here you go to the opposite side of the spectrum with a life-threatening story... got something more in the middle?
 
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