Our Dumb Mistakes

Puppy related raves and general interest that doesn't fit anywhere else
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greengeek
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#31 Post by greengeek »

prehistoric wrote:You wouldn't have lasted long in the environment where ....... some of those bus bars were floating at 400 volts.
True enough. I wonder what the frying time of human flesh at 400v is. 60 seconds maybe?? Mmmmm, smells like chicken...

That reminds me of another mistake I made - I was given the job of replacing the faulty "ON/OFF" switch in an 80 column card punch and I happily yanked the spade wires off the back of the switch - having forgotten to unplug the cord from the wall. Zzzzzt.

I managed to throw the switch right across the room and swore like a trooper, much to the customers amusement. Lesson learned.

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puppyluvr
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#32 Post by puppyluvr »

:D Hello,
LOL...
I recently had a box go down after moving it.. Video failed completely.. Nada..
Had a geforce card in it, which I assumed had failed.. Removed it and attached to the onboard intel, reset the jumpers, and rebooted.. Still nothing at all.. Not even the bios framebuffer.. Crap.. Removed the disks, the cd/dvd, and replaced the ram, to no avail.. Checked all the jumpers, the ram slots, even tested the MB clip on the power supply.. Only after giving up in disgust after a few hours, when I removed the tower from the desk, did I realize I had plugged in the wrong monitor cord.. :roll:
I once turned off the wrong breaker to a 440 volt 60hp power source, and then stuck a screwdriver into a box, and blew the end off it, and my finger..
The video card thing still pissed me off more.... :wink:
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8-bit
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#33 Post by 8-bit »

At one time, I worked as a millwright at a small lumber mill that made agricultural stakes.
I was also a regular worker there since it did not require a full time millwright.
I had another worker complain to me that he was being shocked by a machine he was feeding.
I touched the machine and did not get shocked so I thought I would investigate further.
When I did not get shocked, I was standing on a wooden floor.
I then went to clean out some wood on a trough conveyor and happened to touch the machine in question.
I now know what it feels like to be the ground for a 440 volt 3phase circuit.
It turned out that when the mill was originally wired, the conduit was used as a ground.
The conduit had separated and wore through one of the power wires.
And with the conduit separated the machine had what they would call a floating ground.
So anyone that was grounded and happened to touch the machine completed the circuit.
Not a good thing!

I had the machine then shut down, locked out at the breaker, and established a good ground for it as well as repairing the bad wiring.
But I did learn that when one goes to test that a meter is a lot safer than touching the machine to check for a short!

I guess you could say I got recharged that day!

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lwill
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#34 Post by lwill »

Not Puppy, but linux.
I updated to Fedora 18 with KDE on one machine and since then the "device notifier" applet would always ask for root password to mount cd/dvd/usb/sd drives when inserted. Never had before. No biggy, but annoying.
Spent half the day searching for reasons. Permissions, settings, mounting settings. Lots of google.
Turns out in the "default applications", the default file manager was set to "Konqueror ROOT" for some reason. I have an icon on the tool bar set to open my home folder that uses Dolphin (which is the normal fedora default) so I never try to open a directory directly and never actually used the "default" file manager.
.
.
On further thought, I may have done it to myself at some point. I was working with Android / linux on a Mele 2000 using sd cards to transfer stuff and needed to be root to modify files on them.

Still half a day I lost fixing it!!

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prehistoric
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#35 Post by prehistoric »

lwill wrote:...Still half a day I lost fixing it!!
Only half a day? Hardly worth mentioning.

How about the better part of a stressful week?

This story relates to the earlier business about high voltage in a strange way, we were simulating a device which used a traveling-wave tube -- because not only did these things cost about $15,000 apiece, there was a real problem of losing students if they reached into the case without turning the power off. (We're talking thousands of volts, with kilowatts of power.) It also has some relevance to assumptions about the polarity of ground.

Naturally, we were dependent on an expert instructor for testing our simulated device. Nobody wanted to fool with the real thing, even if we were allowed to. (The device was classified, which made it hard to access data about it.) The one expert we had that week told me I had one control "backwards" on the simulator, as opposed to the real device. I questioned him about this with a graph of the performance of some parameter versus voltage on that knob in front of us. When I thought I understood, I went off and reprogrammed. This was not a simple task, because of other factors that would take us too far afield. Any substantial change cost me hours of work. I went through this drill three times. Each time it remained "backwards", and I became more confused.

On the last day of this fiasco I walked into the room housing our simulator, and saw a technician resoldering the wires on the potentiometer controlling the (simulated) voltage which was the problem. It turned out what our expert meant by "backwards" had nothing to do with the voltage on the graph; he meant the real knob rotated counterclockwise to increase voltage. My original program had been correct, but under pressure of all the changes made in a hurry I was no longer sure which version I should use.

I ended up reprogramming that control from scratch one last time. It only took me a little over an hour, because of all the practice I had had. A simple question about clockwise versus counterclockwise could have saved most of a week. Fortunately, errors with simulated voltages don't kill people.

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greengeek
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#36 Post by greengeek »

prehistoric wrote:...he meant the real knob rotated counterclockwise to increase voltage.
Interesting the assumptions we make. My guts tells me that it is just plain "wrong" to have the voltage increasing when you turn the knobby counterclockwise - but there is no real justification for my rationale. Whoever wired up the real knobby in that direction was a knobby themselves.
:-)
Or maybe thats just how things go in the northern hemisphere? Like bathwater draining the wrong way...

EDIT: I suppose if the knobby was marked "ATTENUATION" then it MIGHT be ok to be decreasing the voltage in a clockwise direction. Otherwise its just not ok to do that. Never. Not ever. (Unless there's a good reason). :?

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puppyluvr
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#37 Post by puppyluvr »

:D Hello,
CW is on, CCW is off..
"righty tighty, lefty loosey" (except old Mopar.. :roll: )

As a teenager, while hunting deer with my younger step-brother Bobby, I witnessed him urinating on an electric cattle fence... :shock:
After the convulsions went away, and the screaming subsided, and I quit laughing enough to check, he seemed to be OK... :roll:
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prehistoric
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#38 Post by prehistoric »

greengeek wrote:...Interesting the assumptions we make. My guts tells me that it is just plain "wrong" to have the voltage increasing when you turn the knobby counterclockwise - but there is no real justification for my rationale. Whoever wired up the real knobby in that direction was a knobby themselves.
:-)
Or maybe thats just how things go in the northern hemisphere? Like bathwater draining the wrong way...

EDIT: I suppose if the knobby was marked "ATTENUATION" then it MIGHT be ok to be decreasing the voltage in a clockwise direction. Otherwise its just not ok to do that. Never. Not ever. (Unless there's a good reason). :?
There was an excellent reason -- all the other controls had the opposite polarity. The graph I was using as a reference didn't mention that. I suppose they just assumed anyone familiar with the device would know.

I will note, in passing, that modern traveling-wave tubes are designed with the idea that it is ridiculous to have a mere human technician directly controlling each parameter. There are sophisticated circuits between people and those adjustments. That simulator was scrapped long ago.

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prehistoric
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#39 Post by prehistoric »

puppyluvr wrote:... As a teenager, while hunting deer with my younger step-brother Bobby, I witnessed him urinating on an electric cattle fence... :shock:
After the convulsions went away, and the screaming subsided, and I quit laughing enough to check, he seemed to be OK... :roll:
Does he have any children?

I know of an entire fraternity which is reproductively challenged as a result of an initiation involving pissing on a running lawnmower.

Dewbie

#40 Post by Dewbie »

prehistoric wrote:
I know of an entire fraternity which is reproductively challenged as a result of an initiation involving pissing on a running lawnmower.
An electric mower?
Or was it blade-related? :roll:

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Amgine
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#41 Post by Amgine »

prehistoric wrote:
puppyluvr wrote:... As a teenager, while hunting deer with my younger step-brother Bobby, I witnessed him urinating on an electric cattle fence... :shock:
After the convulsions went away, and the screaming subsided, and I quit laughing enough to check, he seemed to be OK... :roll:
Does he have any children?

I know of an entire fraternity which is reproductively challenged as a result of an initiation involving pissing on a running lawnmower.
Our best and brightest, our college educated. :roll:
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infromthepound
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#42 Post by infromthepound »

In the early days of USB the connecting cables were individual instead of one block and not that well marked. (Stupid idea, some still are).
It was not that obvious how to do it on one motherboard and I connected power and ground the wrong way round.
Smoke, and I needed another motherboard.
JB

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prehistoric
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#43 Post by prehistoric »

Dewbie wrote:[...An electric mower?
Or was it blade-related? :roll:
Just in case you are serious, it was a gasoline burning mower. The problem was the spark plug.

I also have a story about an extremely embarrassing incident which happened to a guy in the army. I got it from the man in the next hospital bed. He was out on an artillery range at Ft. Sill when he pulled the pissing on an electric fence stunt. (They didn't keep cattle there, but they did have buffalo. Maybe these require stronger shocks.)

He was alone at the time. This meant he had to get in the jeep with his pants unzipped, and drive himself to the hospital. By the time he got there swelling meant he was in no condition to either walk or cover himself. He drove up to the emergency room entrance and leaned on the horn. Then he had to explain why he was there before they called for MPs.

Something that happened in the confusion of the accident required stitches. This meant he had to avoid erections for a week or two. He was given a can of Freon to cool things off. One problem developed when nurses from other floors came to visit my friend in the next bed. (He was popular with the ladies.) To be polite, they tried to pay a little attention to the man in the other bed, who really didn't want to explain his problem. He had to ask them to leave without giving much explanation in order to use the Freon.

Dewbie

#44 Post by Dewbie »

prehistoric wrote:
Just in case you are serious, it was a gasoline burning mower. The problem was the spark plug.

I also have a story about an extremely embarrassing incident which happened to a guy in the army...he pulled the pissing on an electric fence stunt.
I believe the clinical term (in both cases) is Erectrocution.:twisted:

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Karl Godt
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#45 Post by Karl Godt »

Colonel Panic wrote:When logged in as root on my Pentium 100 running Basic Linux, I tried to erase a directory using the rm command and wiped the whole drive instead. I make full backups to USB drive and DVD now (I didn't then).
Did such similar with one Xubuntu full installation . Must say i don't miss it . :lol:
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People who want problems with Puppy boot frugal :P

Ibidem
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#46 Post by Ibidem »

puppyluvr wrote: As a teenager, while hunting deer with my younger step-brother Bobby, I witnessed him urinating on an electric cattle fence... :shock:
After the convulsions went away, and the screaming subsided, and I quit laughing enough to check, he seemed to be OK... :roll:
A saying I heard from my first college ag teacher:

"There are three kinds of people in the world:
Those who learn by reading,
Those who learn by seeing,
And those who just have to pee on the electric fence for themselves."

A little thing he mentioned: the wrong way to test an electric fence for current is with the inside of your fingers. Besides the shock itself, sometimes the current makes your hand curl closed around the wire. A trick that's sometimes helpful is to hold a blade of grass near and listen--if your ears are good enough! If you must use your hand, use the back.

Also, it's annoying to have a mower that won't turn off when you release the handle: there's a small jolt when you disconnect the spark plug to stop it.

But my biggest oops was the time I drove through a "puddle", on the downhill side. I thought it looked reasonable to cross, as I always had managed to do so previously--until my car stopped 1/3 of the way across. Wading across a hundred feet of knee deep puddle is not fun; less so when it's in pouring rain an hour before finals...
(Nothing like a jumpstart and starter fluid in the air intake to get it started again!)

akash_rawal
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#47 Post by akash_rawal »

I felt really helpless when I committed the mistake of mounting all drives in /tmp, forgetting to unmount them and shutting down the system.

I was wondering, why was puppy taking so much time to shut down :?

Next boot discovered that none of the linuxes were bootable.

Had to buy a new CD to run puppy and discovered that all my linux partitions were empty.

From that day I never mount anything under /tmp.

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Flash
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#48 Post by Flash »

Why did mounting the partitions under /tmp cause them to disappear when you shut the computer down? If you'd simply unplugged the computer, rather than shutting it down in software, do you think the same thing would have happened?

akash_rawal
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#49 Post by akash_rawal »

Flash wrote:Why did mounting the partitions under /tmp cause them to disappear when you shut the computer down? If you'd simply unplugged the computer, rather than shutting it down in software, do you think the same thing would have happened?
I think all files in /tmp are deleted one by one while shutting down.

Strangely only linux partitions were emptied, my data on ntfs partitions were intact so I was able to recover the system.

In this case it seemed safer to cut off power supply than shutting down the computer. :lol:

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rcrsn51
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#50 Post by rcrsn51 »

akash_rawal wrote:I think all files in /tmp are deleted one by one while shutting down.
I once made the same mistake by mounting a digital camera's memory on /tmp, then shutting down Puppy while the camera was still turned on.

I couldn't figure out why all my pictures were disappearing.

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