Author Topic: Most embarrassing junior tech moment? Go!  (Read 4862 times)

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Offline mkiijamTopic starter

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Most embarrassing junior tech moment? Go!
« on: May 11, 2023, 01:43:27 am »
I once installed a transistor (H.O.T.) backwards. When the senior tech looked at the TV to see why it wouldn't work, he immediately noticed the error. "Did you install this...backwards?" "Uh... oh!" I said, playing it off like a simple mistake, But the truth was, and here's the embarrassing part, I had no idea what he was talking about. "They have front ways and backways???" is all I remember thinking!
 
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Online EEVblog

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Re: Most embarrassing junior tech moment? Go!
« Reply #1 on: May 11, 2023, 02:02:45 am »
My first job at Pacific Communications. Late at night pizza session trying to finish firmware (Z80) for a client demo the next day, I was the testing guy.
Firmware guy burns the EPROM and gives it to me to test. I of course proceeded to install it backwards and the magic smoke escapes. That was our only EPROM of that size  :palm:
 
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Offline thermistor-guy

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Re: Most embarrassing junior tech moment? Go!
« Reply #2 on: May 11, 2023, 05:12:27 am »
Student job at a Telecom Australia lab, back when Telecom (now Telstra) had labs.

One of the Tech officers asked me to complete the build of a 12VDC to 240 VAC converter, and test it. It used TO-3 power BJTs.

Build complete and powered up. With my left hand I touched one of the TO-3 cases. Hmm, hot but not too hot. Then, with my
left hand still in contact, I touched the other case with my right hand.

One of the techs had to shoulder me aside, to break the circuit. Apparently I was just standing there, not breathing, my eyes all weird.
He told me he felt a shock when he shoved me clear.

The lab techs believed that fresh Engineering Uni students know nothing, and pose a danger to themselves. Hypothesis confirmed.
« Last Edit: May 11, 2023, 05:18:09 am by thermistor-guy »
 
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Offline JPortici

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Re: Most embarrassing junior tech moment? Go!
« Reply #3 on: May 11, 2023, 05:37:09 am »
crocodile clips from the power supply slips from my hand.
of course they fall over the MCU causing a bang and some smoke
 

Offline Halcyon

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Re: Most embarrassing junior tech moment? Go!
« Reply #4 on: May 11, 2023, 06:18:20 am »
One of the techs had to shoulder me aside, to break the circuit. Apparently I was just standing there, not breathing, my eyes all weird.
He told me he felt a shock when he shoved me clear.

Gees! Lucky you're still here!
 
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Offline thermistor-guy

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Re: Most embarrassing junior tech moment? Go!
« Reply #5 on: May 11, 2023, 06:40:31 am »
...
Gees! Lucky you're still here!

Absolutely.

The Lab had an iron rule - no-one works in the lab alone. I wouldn't be here if I had broken that rule.
« Last Edit: May 11, 2023, 06:42:06 am by thermistor-guy »
 

Offline David Hess

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Re: Most embarrassing junior tech moment? Go!
« Reply #6 on: May 11, 2023, 02:43:41 pm »
Most embarrassing?

I once installed several banks of socketed DRAM backwards.  Luckily the hundreds of dollars worth of DRAM chips survived.

I picked up a heavy 25,000 volt neon sign transformer by the insulators ... while it was powered.  Luckily I managed to set it down rather than throwing or dropping it.

Caught my hair on fire in the chemistry lab.
 

Offline joeqsmith

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Re: Most embarrassing junior tech moment? Go!
« Reply #7 on: May 11, 2023, 05:09:32 pm »
A couple of my early stories.
 

Offline Black Phoenix

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Re: Most embarrassing junior tech moment? Go!
« Reply #8 on: May 11, 2023, 06:01:57 pm »
555 timer was not making his function. Me, a newbie who also at the time was in the PC Overclocking community thought that extra voltage would be the solution for it.

Ended with an audible pop and a crack on the substrate. Replaced the timer, forgot to change the voltage, another one to the trash...
 

Offline madires

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Re: Most embarrassing junior tech moment? Go!
« Reply #9 on: May 11, 2023, 06:03:07 pm »
Junior tech in a data center was told to install an additional card in a Catalyst 6500 (big and expensive switch). He somehow managed to insert the card upside down by applying unreasonable force and let the magic smoke out. That was a US$ 50k+ oopsi.
 

Offline tom66

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Re: Most embarrassing junior tech moment? Go!
« Reply #10 on: May 11, 2023, 06:11:14 pm »
On my internship, I broke an £800 low impedance high bandwidth scope probe by pressing too hard and snapping the (apparently non-serviceable) tip.   :-BROKE
 

Offline David Hess

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Re: Most embarrassing junior tech moment? Go!
« Reply #11 on: May 11, 2023, 08:05:16 pm »
Oh, yea, I once did a board layout where I reversed power and ground on just half of it.
 

Offline Njk

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Re: Most embarrassing junior tech moment? Go!
« Reply #12 on: May 11, 2023, 09:35:56 pm »
Designed a new board version, that uses a cable for power and signals. For better PCB layout, changed power and ground pins in the cable connector. Sent the engineering note to the factory in China, requesting to manually swap the PWR and GND pins in the existing cable stock. But the factory guys are very smart and well trained. They quickly realized that the pins in the cable connector needs to be swapped. On reception of my note, they swapped the pins one more time, resulting in the original configuration...
 

Offline aeberbach

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Re: Most embarrassing junior tech moment? Go!
« Reply #13 on: May 11, 2023, 10:22:26 pm »
Dataplex, around 1995 - I installed a (very expensive) 540MB 2.5" hard drive in a prototype controller for a SNMP-managed bank of modems. A chip on the bottom of the drive exploded, a piece flying across the room. Of course it was NOT the engineer's fault for using a non-keyed drive connector, it was mine for not knowing that he had and which way was it was supposed to go!
Software guy studying B.Eng.
 

Online themadhippy

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Re: Most embarrassing junior tech moment? Go!
« Reply #14 on: May 11, 2023, 11:35:31 pm »
mistaking the  fire alarm circuit for a socket circuit,meter out  to confirm its dead and bells started ringing,one office evacuation  and 2 fire engines  later  i found the correct cable.
« Last Edit: May 11, 2023, 11:37:16 pm by themadhippy »
 

Offline PwrElectronics

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Re: Most embarrassing junior tech moment? Go!
« Reply #15 on: May 12, 2023, 02:59:33 am »
Hand made single sided through hole PCB.  I made maybe 3-4 of them.  I had a 1-1 photo negative of the plotter output from AutoCAD v12 for DOS that I was using.  Brute force hand layout not suited for PCB work at all.  I used the negative with photo-sensitized boards.  Place the negative over the board and expose it (outside in the sun, no black lamp available) then rinse and etch and hand drill it.  This could take most of the work day to make one board.

So, I made one of these boards and didn't notice I had the negative upside down when I exposed it until I went to insert parts  :palm: :-[

It was the cleanest etch of all of them I made and it was junk.  I have it someplace...
 

Offline Berni

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Re: Most embarrassing junior tech moment? Go!
« Reply #16 on: May 12, 2023, 05:59:33 am »
Hand made single sided through hole PCB.  I made maybe 3-4 of them.  I had a 1-1 photo negative of the plotter output from AutoCAD v12 for DOS that I was using.  Brute force hand layout not suited for PCB work at all.  I used the negative with photo-sensitized boards.  Place the negative over the board and expose it (outside in the sun, no black lamp available) then rinse and etch and hand drill it.  This could take most of the work day to make one board.

So, I made one of these boards and didn't notice I had the negative upside down when I exposed it until I went to insert parts  :palm: :-[

It was the cleanest etch of all of them I made and it was junk.  I have it someplace...

Yep did that one a few times back when etching PCBs. My solution for it was to start always putting some text somewhere on the board or at least outside the board area, so that if i can't read the text it is wrong.

I did soon start printing the transparency mirrored on purpose because that meant when flipped correctly the ink was on the bottom side, so it is closer to the PCB and gives a sharper result.
 

Offline jonpaul

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Re: Most embarrassing junior tech moment? Go!
« Reply #17 on: May 12, 2023, 11:03:53 am »
1970 my second job as an EE.
Vibration/Real Time FFT analyzer system in 6' rack.
Drove  to demo at  Wash DC  wtih  my  manager.

In the hotel room, Assembled units into the rack, and plugged in 100 pin cable connectors.

Turn ON! HUGE bang , smoke from EVERY rack unit!

It had an oven for a VCO or Xtal, heater had 120V mains.

Turned out the plugs were not ploarized!

One plug with 120V was reversed and the mains hit a common clock bus, blowing up may TTL ICs on many units and boards.

Worked all night and by moring it was sort of doing something, at least not blowing up.

Off to the Gov Demo, it WORKED enough...they did not notice the remaing bugs...

Walked away from another one....

Jon



An Internet Dinosaur...
 
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Offline TERRA Operative

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Re: Most embarrassing junior tech moment? Go!
« Reply #18 on: May 12, 2023, 12:13:37 pm »
Junior tech in a data center was told to install an additional card in a Catalyst 6500 (big and expensive switch). He somehow managed to insert the card upside down by applying unreasonable force and let the magic smoke out. That was a US$ 50k+ oopsi.

I was on the receiving end of a damaged line card a few years back.

It was for a Juniper router and worth US$52,000. I opened the box and almost slid it into place when I luckily noticed the smashed backplane connectors before I tried to seat it home in the mainframe...

No damage on the outside of the box, so the tech who packed it must have dropped it and stuck it in the box anyway, hoping we could claim insurance from Fedex.

Unfortunately, logistics, in an attempt to save money, only declared its value as a few hundred dollars, so the cost of a new card had to be eaten by my employer ....
Some frantic emails to Juniper begging for repair, but they (understandably) said NOPE! As they were not willing to take the liability and warranty obligations for any hidden damage in a piece of critical internet infrastructure. A single cracked trace or intermittent connection and nightmares ensue..
Could you even pull a 200+ pin press-fit backplane connector from a 15+ layer PCB without damage? The PCB was like 5mm thick! :-/O

I have noticed things are declared at much closer to their real value since then. :D I bet there were a few spanked bottoms over that one..  :-DD
Where does all this test equipment keep coming from?!?

https://www.youtube.com/NearFarMedia/
 

Offline TERRA Operative

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Re: Most embarrassing junior tech moment? Go!
« Reply #19 on: May 12, 2023, 12:25:45 pm »
Oh, another one.

Back when I was in the water treatment game, we were servicing the UV sterilising system that would disinfect the water as a last step before leaving the sewerage treatment plant back into the ocean.
The UV tubes were long quartz fluorescent tubes without the phosphor (like a massive UV EPROM eraser tube) all racked up in quartz 'test tubes' with double o-ring plugs in the end and submerged into the canal.
IIRC there were 2 banks in sucession, each consisting of 4 racks wide each holding 12 tubes arranged 6 tall, 2 wide.

We were cleaning the insides of the tubes as the UV light along with the small amount of moisture leakage and other science reasons forms a brown coating on the quartz 'test tubes' which requires the use of phosphoric acid to clean off.

The guy I was working with wasn't wearing gloves, which I warned him about but because the acid didn't immediately burn, he dismissed my warnings and said he's fine.  :popcorn:

Well..... the next day... his hands looked like they had been underwater for a week and the top layer of skin was sloughing off.
Dude basically gave himself an epic chemical exfoliation.  :palm:

He wore gloves religiously after that. I bet his hands were sensitive for aaageess  :-DD
Where does all this test equipment keep coming from?!?

https://www.youtube.com/NearFarMedia/
 
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Offline Black Phoenix

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Re: Most embarrassing junior tech moment? Go!
« Reply #20 on: May 12, 2023, 12:44:39 pm »
Oh, another one.

Back when I was in the water treatment game, we were servicing the UV sterilising system that would disinfect the water as a last step before leaving the sewerage treatment plant back into the ocean.
The UV tubes were long quartz fluorescent tubes without the phosphor (like a massive UV EPROM eraser tube) all racked up in quartz 'test tubes' with double o-ring plugs in the end and submerged into the canal.
IIRC there were 2 banks in sucession, each consisting of 4 racks wide each holding 12 tubes arranged 6 tall, 2 wide.

We were cleaning the insides of the tubes as the UV light along with the small amount of moisture leakage and other science reasons forms a brown coating on the quartz 'test tubes' which requires the use of phosphoric acid to clean off.

The guy I was working with wasn't wearing gloves, which I warned him about but because the acid didn't immediately burn, he dismissed my warnings and said he's fine.  :popcorn:

Well..... the next day... his hands looked like they had been underwater for a week and the top layer of skin was sloughing off.
Dude basically gave himself an epic chemical exfoliation.  :palm:

He wore gloves religiously after that. I bet his hands were sensitive for aaageess  :-DD

Had a similar situation when I was working on the CNC machines. The company also were selling UV treatment equipment, from Hanovia.

I didn't do instalation of the equipment but the preventive maintenance, replacement of seals, lamps, quartz tubes etc was done by the maintenance team. I had a little of phosphoric acid fall on my arm skin and heck did I look like a snake sheading skin...
 

Offline srb1954

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Re: Most embarrassing junior tech moment? Go!
« Reply #21 on: May 12, 2023, 01:12:17 pm »
Back in the olden days when I first started using CMOS devices I found that debugging such circuits was a little different from the TTL circuits I had previously been used to.

I had a new logic board for testing but was having some trouble to get it working correctly. It seemed to work most of the time but for some combinations of inputs the logic gave incorrect results. After wasting a few hours checking and rechecking the logic design I realised I had forgotten to turn the PSU on when starting testing that morning!  :palm:

The whole board was being powered by the pulse generator providing the clock input. There was enough current being coupled through the protection diodes on the clock input chip to power the logic most, but not all, of the time.
 
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Offline ShaunT

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Re: Most embarrassing junior tech moment? Go!
« Reply #22 on: May 12, 2023, 01:18:24 pm »
Well this was at college but it was a job our tech should have done.
I was ahead in A level electronics so while everyone was on TTL and playing with transistors I had moved onto CMOS gates. We shared a power supply with a box termination in banna sockets. So my circuit kept false triggering and placing a local electrolytic cap did not work. So I fitted electrolyic caps to ALL boxes. Then someone for a joke swapped the leads to the power supply which normally only kills a couple of projects but this time the ALL the boxes exploded with plastic shower of shrapnel. I was in another lesson and watched as this very stunned kid was taken to headmaster for causing so much damage.
That's how I learned about decoupling and one electrolyic is not enough and may need to add sat a ceramic rather than keep having bigger capacitance!
Back in the eighties when we could not afford individual power supplies as cheap as now and just have one big one for all which I think came from a telephone exchange!
 

Offline armandine2

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Re: Most embarrassing junior tech moment? Go!
« Reply #23 on: May 12, 2023, 01:22:26 pm »
mildly embarrassing moment

company made bespoke SPC (statistical process control) test measurement rigs with LVDT transducers. I removed one of a rig's component blocks from a unit without first removing the two LVDTs which were in that block. In doing so I sheared the tip ends of the LVDTs  :palm:

I still blame the poor design. Though it was a good unit - used on Ford Galaxy ignition block die castings.
In a closed society where everybody's guilty, the only crime is getting caught - Hunter S Thompson
 

Offline madires

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Re: Most embarrassing junior tech moment? Go!
« Reply #24 on: May 12, 2023, 02:46:19 pm »
The small and harmless things can be quite entertaining too. At the university we had a few computer rooms including one with SPARstation IPCs (small Unix workstation, see https://en.wikipedia.org/wiki/SPARCstation_IPC) and large Sun CRT monitors. The IPC comes with a 3.5" floppy drive. For one course we had to write some unix shell scripts and save them on a floppy disk. So you insert the floppy disk, copy the scripts, and then you suddenly realize there's no button to get the disk out of the drive...

There's a shell command to eject the floppy disk.

The large Sun monitors came with remote controls, similar to the small ones for car stereos or LED controllers. Of cource they were locked up in some drawer, but a student working as tutor had one. And he had a lot of fun with his RC and some students he didn't like.


 


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