Post your biggest easy mistake here... / General Chatting / Forums

Forums

4hv.org :: Forums :: General Chatting

« Previous topic | Next topic »

Post your biggest easy mistake here...

1 2 3 next

Move Thread

LAN_403

Inducktion

Tue Jun 21 2011, 06:16PM

Registered Member #3637 Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068

Post whatever easy mistakes you've made in the past that could have been easily avoided... Like hooking up stuff backwards!

I've broken the leads off of a few mosfets on accident, It's not fun when it's an expensive part :P

Chip Fixes

Tue Jun 21 2011, 06:19PM

Registered Member #3781 Joined: Sat Mar 26 2011, 02:25AM
Location:
Posts: 701

A while back I accidently blew up a flyback driver I had just bought because i didn't know what i was doing. Blue smoke everywhere!! and I'm no longer allowed to work on electronics in the living room

Unfortunately, I forgot to pull out the ferrite core before i threw it out

Forty

Tue Jun 21 2011, 06:58PM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

I built the plasma speaker II from teravolt.org, had exact value components for everything, all breadboarded up, and connected the power backwards on the breadboard strips. fried the sg3525 chip and i only ordered one of them.
i also misplaced a diode in a coilgun. should of been diode in series with paralleled capacitor and coil but instead i had the diode and coil in series, with that in parallel with the caps. full discharge through 80A peak diode = plasma deposited metal coating on inside of plastic enclosure.

Conundrum

Tue Jun 21 2011, 08:12PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

I've had this happen on laptop power bricks before.
Whatever happens one of the input resistors disintegrates and metal plates everything inside the case near it.

-A

Avalanche

Tue Jun 21 2011, 09:07PM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

I work at a company that deals with power electronics, and occasionally I go out onto customers sites to work on our equipment (in this case electric rail shunters). On this occasion, I had just spent several hours modifying the traction inverter software which drives 4x 5kW brushless AC motors, and I had finally got all 4 motors producing full torque at standstill whilst staying stable (the previous software had been going nuts). Then I fell down the inspection pit.

Fabio

Thu Jun 23 2011, 08:00AM

Registered Member #122 Joined: Fri Feb 10 2006, 12:55PM
Location: Milano Italy
Posts: 148

Red jack in the black plug and viceversa..... this is a classic big mistake!!!!

Another "power supply classic mistake", first connect the leads, so switch the power supply on and than adjust the voltage..... sometimes may NOT work (expecially if a 3.3V is needed and the powersupply was previously used at 30V)

rp181

Thu Jun 23 2011, 11:18AM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

I had a large, brand new stud SCR (3/4" diameter stud). It was rated for 5kA surge, and it was very underrated compared to the sizes of other SCR's.
I connected the cap bank to the gate, and it blew up next to my face.

Another time, on my 12kJ cap bank, a connection was a tiny bit loose, and it blasted a 1/4" bolt away.

Dr. Slack

Thu Jun 23 2011, 12:26PM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

I was fault-finding a fairly expensive bit of kit. In order to manually control some of the logic bits, I soldered an insulated wire I had to hand, long(ish) and thick(ish), to a point on the 5v rail, and then dabbed the other end of it onto various control lines - no problem so far. Then I let go of the wire. Being thick, it was fairly springy, and as I watched it described a beautiful curve through the air, too fast for me to catch it again. This is the moment that lasts an OhNoSecond, somewhere between a moment and a lifetime. Had it hit the case, it would have shorted the supply, which would have been OK. Had it hit a sensitive component, it would have probably destroyed it, but would have not been too bad. It hit the +24v terminal of a large electrolytic in the power supply. The 5v line shot up to 24v, taking out every 5v IC in the entire instrument. Ouch!

ScotchTapeLord

Thu Jun 23 2011, 08:19PM

Registered Member #1875 Joined: Sun Dec 21 2008, 06:36PM
Location:
Posts: 635

I forgot to ground the entire circuit, as in there was no return path at all, save for the few femtofarads from ground plane to the negative supply. But strangely enough, half of the circuit was working so I was very confused for a while. Silly CMOS logic. Guess I will put my on/off switches on the high side from now on...

Nah

Fri Jun 24 2011, 01:50PM

Registered Member #3567 Joined: Mon Jan 03 2011, 10:49PM
Location: USA, 1960s
Posts: 260

I thought that some solder was wire.....

1 2 3 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob