I remember upgrading memory and wondering why the PC would not start/boot... niente, nix, nothing...

I took the whole motherboard apart trying to figure out what was wrong until I saw I had removed the power plug from the back....

I just remembered two, I once "gleeked" on a mainboard and short-circuited it.
I gleek randomly all the time and it happened when I was testing my Soyo slot1 system.
There wasn't any permanent damage but I learned to keep my mouth shut when I'm working with electronics.

I used to store my spare parts in the attic and it gets really cold there during the winter.
I needed a PSU replacement so I took one down but neglected to wait for it to actually warm up to room temp.
I turned it on and the PWM IC instantly blew up because of the condensation.

Just a couple of weeks ago I was messing around with a KVM switch that would allow me to use a single PS/2 keyboard and mouse for up to 4 machines. Luckily tested it with just one connected -- something must not have been quite right because when i booted, no keyboard recognized. Thought it was just the switch not working right, so connected keyboard directly...still nothing.

Turns out a blew the fuse the protects the PS/2 ports -- which i now need to replace. I found the fuse, but now have to hone my desoldering/soldering skills before attempting the fix. Just glad i didn't do irrepairable damage...

I had always heard horror stories about hot-swapping PS/2...now i know they are true.

I was 14 and switched from a Zenith Data System 386 with 3.1 to a Pentium 75 with Windows 95.
After only 2 days I decided to try to install a desktop replacement I used to have for windows3.1 . I believe it was PC Tools. It has completely crashed w95. I had to reinstall it but the Graphic card drivers ( s3 virge I think ) was not the right one so I was limited to 256 colors...
Without internet it took several weeks/months to get it fixed !

antrad wrote on 2020-07-16, 03:56:

My biggest mistake was throwing away my first computer.

Same. I was 15 at the time and I didn't know better. Still, I miss that damn thing.
I also regret throwing out that CRT my dad had got me from a CAD business. That thing was able to do QXGA! 🙁

But back then it was just old junk. Who would've thought I'd need this in 2020 anyway?

Hot plugging the PS2 keyboard port on my old PPro server. I ended up replacing the board. I never could find a fuse on the original.

Recently I misjumpered a slocket adapter for 3.3V with a Coppermine CPU. When it didn't finish POSTing I checked voltages and saw the 5V rail sagging to 4.8V and Vcore at 2.9V.
It survived.

Had a PSU fall on an AGP card and bend the slot. I bent it back and it still works.

I got a phone call from somebody who was shopping for a RAM upgrade. They removed a RAM stick to look at it. Windows gave them an error message, so they put it back in. Magic smoke.

shamino wrote on 2020-07-25, 01:01:

I got a phone call from somebody who was shopping for a RAM upgrade. They removed a RAM stick to look at it. Windows gave them an error message, so they put it back in. Magic smoke.

Not quite your mistake, strictly speaking . That said, I feel like there is more to this story .

Miphee wrote on 2020-07-16, 16:29:

I just remembered two, I once "gleeked" on a mainboard and short-circuited it. I gleek randomly all the time and it happened whe […]
Show full quote

I just remembered two, I once "gleeked" on a mainboard and short-circuited it.
I gleek randomly all the time and it happened when I was testing my Soyo slot1 system.
There wasn't any permanent damage but I learned to keep my mouth shut when I'm working with electronics.

I used to store my spare parts in the attic and it gets really cold there during the winter.
I needed a PSU replacement so I took one down but neglected to wait for it to actually warm up to room temp.
I turned it on and the PWM IC instantly blew up because of the condensation.

I remember I working on an old Power Macintosh G3 Blue & White and I had just washed my hands, and "thought" I had dried them good, well a drop of water from the hair on my arms/wrists fell onto one of the RAM chips and "poof" there it went, thankfully it was just normal PC100 memory, and no damage happened computer.

I seem to remember in the late 1990s trying to put a very large motherboard into a very small computer case and one of the brass standoffs scratched the motherboard cutting a trace on the bottom of the motherboard and killing it.

Another time when I was at college taking a computer class, I got distracted when working on a computer because I was talking to my classmates, and I closed up the computer case pinching the power/reset/led wires going to the motherboard and the computer caught fire, this happened in the early 2000s and it was an old white box Pentium 100.

darry wrote on 2020-07-25, 01:08:

shamino wrote on 2020-07-25, 01:01:

I got a phone call from somebody who was shopping for a RAM upgrade. They removed a RAM stick to look at it. Windows gave them an error message, so they put it back in. Magic smoke.

Not quite your mistake, strictly speaking . That said, I feel like there is more to this story .

They called to ask what could be done about the blacked out RAM slot that wasn't working anymore, and that's how he explained what happened. No it wasn't my mistake, I just tacked it onto the list.
I think he bought a new motherboard.

shamino wrote on 2020-07-25, 03:00:

darry wrote on 2020-07-25, 01:08:

shamino wrote on 2020-07-25, 01:01:

I got a phone call from somebody who was shopping for a RAM upgrade. They removed a RAM stick to look at it. Windows gave them an error message, so they put it back in. Magic smoke.

Not quite your mistake, strictly speaking . That said, I feel like there is more to this story .

They called to ask what could be done about the blacked out RAM slot that wasn't working anymore, and that's how he explained what happened. No it wasn't my mistake, I just tacked it onto the list.
I think he bought a new motherboard.

Thank you . I had imagined something more along the lines of somebody forgetting to tell the dude handling the computer to turn it of before playing with RAM. In this case, the dude broke things all by himself .

Probably turning on a NOS Seasonic power supply on 220V mains with the switch set to 110V. In my defense, I was going through a big haul of retro stuff and was really tired by that point. The loud "bang" and the spark sure startled me!

I consider it karma for laughing at a poor infrastructure guy in the office who had the same thing happen to him when setting up brand new PCs during his 2nd or 3rd day on the job!

In any case, I luckily managed to fix the Seasonic PSU by replacing a varistor and the fuse (also recapped it once I confirmed it was working again). It has since been powering up a Slot 1 PC.

TheMobRules wrote on 2020-07-25, 05:29:

Probably turning on a NOS Seasonic power supply on 220V mains with the switch set to 110V. In my defense, I was going through a big haul of retro stuff and was really tired by that point. The loud "bang" and the spark sure startled me!

Did the same thing with my NES when I was 10. It was christmas and I decided to try the little switch on the power adapter. Smoke, system dead, Miphee crying.
I hate these 115/230 switches with a passion because it's an instant death switch waiting to kill your beloved computer when you aren't careful enough.
It's also pointless because why would I ever need 115V in Hungary? I know these are standard designs sold all over the world but it's still cheap and stupid.
If I want a 115V adapter/PSU I'll buy one.
Why won't they make it a 3-way switch to add to the confusion? 400/230/115. That'd be hilarious. /s
But seriously fuk the 115/230 switch.

Miphee wrote on 2020-07-25, 07:13:

Did the same thing with my NES when I was 10. It was christmas and I decided to try the little switch on the power adapter. Smok […]
Show full quote

TheMobRules wrote on 2020-07-25, 05:29:

Probably turning on a NOS Seasonic power supply on 220V mains with the switch set to 110V. In my defense, I was going through a big haul of retro stuff and was really tired by that point. The loud "bang" and the spark sure startled me!

Did the same thing with my NES when I was 10. It was christmas and I decided to try the little switch on the power adapter. Smoke, system dead, Miphee crying.
I hate these 115/230 switches with a passion because it's an instant death switch waiting to kill your beloved computer when you aren't careful enough.
It's also pointless because why would I ever need 115V in Hungary? I know these are standard designs sold all over the world but it's still cheap and stupid.
If I want a 115V adapter/PSU I'll buy one.
Why won't they make it a 3-way switch to add to the confusion? 400/230/115. That'd be hilarious. /s
But seriously fuk the 115/230 switch.

Especially true considering that, even in the early 90s, auto-switching PSUs were a thing . The TTX monitor we had with our first family PC was able to handle anything between 90V and 264V (or something around that), if memory serves .

EDIT: Apparently, my memory is spot on https://www.ttx.ca/monitor-faqs.asp#t3

Here's a fresh one. Small form factor case, and a CF-IDE adapter installed too close to a drive bracket. I guess it made contact when I closed the case up. Luckily this cable adapter took all the damage, and things are still working fine. For now.

About a decade ago:
- Throw out a fully working Amstrad PCW 8512 computer + software + all manuals

Recently:
- Overpay for a parallel 250Mb ZIP drive because I didn't pay attention and thought it was the SCSI variant

Today I connected a SCSI LVD/SE drive to an HVD controller...
The drive has survived.
Can't verify the controller now - any idea what are the chances it's still alive?
Nevertheless, I solemnly swear to thoroughly flog myself!

Grzyb wrote on 2020-08-02, 10:32:

Today I connected a SCSI LVD/SE drive to an HVD controller... The drive has survived. Can't verify the controller now - any idea […]
Show full quote

Today I connected a SCSI LVD/SE drive to an HVD controller...
The drive has survived.
Can't verify the controller now - any idea what are the chances it's still alive?
Nevertheless, I solemnly swear to thoroughly flog myself!

You remind me of an HVD hard drive I bought that was pristine. I was so excited to run that thing that I went shopping for an HVD controller (that part was easy), and an internal 50-pin HVD terminator - which was about the hardest thing on Earth to find. I looked up how to build one myself and thought I was going to have to do that. Digging through ancient usenet posts finally led to a searchable part number that yielded what I needed on eBay, at a price that was not quite so terrible as to keep me from buying it.

Once I had everything together, I hooked up the drive.. and it doesn't really work. I've blamed the firmware on the drive (it was meant for some external disk array thing).

It makes me wonder though, maybe my only issue is the HVD controller card which could have easily been damaged by somebody in the past. Mine reports 0MB capacity and locks up when I tell it to low-level format the drive. If your card ends up showing the same symptoms, I'd be interested to hear it.

Many mistakes like trashing old mainboards or components just for space reason or even AT cases..

But if we talk about errors during installation or similar, well testing a PCI/ISA 486 rare board while late and bored and ending up installing the cpu in the wrong direction and ruining probably both the cpu and the bios/mobo. Still have to understand how to repair it. But also breaking the plastic clips of the 72pin simm socket cause forcing too much the installation but maybe the most incredible I remember was taking out the PCI components after some test of a mainboard and to be sure the system was powered off but insted it was not. Things that usually would never happens but when it's late and you are thinking to anything but the test itself or you're bored .. that can happen. 😁

Pierre32 wrote on 2020-07-31, 03:05:

Here's a fresh one. Small form factor case, and a CF-IDE adapter installed too close to a drive bracket. I guess it made contact when I closed the case up. Luckily this cable adapter took all the damage, and things are still working fine. For now.

Something similar happened with a SATA to IDE adapter for using sata disks on older ide mainboards.. mostly are cheap and with no serious and stable connection on the solder points and one ended up shorting something and literally risking to take fire from the psu cables.
I'll never use cheap adapters again.

I've got a new dumb mistake now. I plugged my front panel usb cable into a 1394 header on the motherboard and then stuck a USB stick in which promptly melted (slight dramatisation - the plastic cover melted). Looking at the pinouts of a a USB2 header and 1394 header I'm not surprised!