A tip for breadboarding (re: explosions)

[cd]

When using bipolar power supplies (like +/-15V) always use the same color wire when wiring the - and + supply, i.e. if all of your -15V are wired with green, don't sub in a red wire (which is wired to all the +15V) because you ran out of green wire and think "oh, I'll remember this one is negative".  Reason: today I was playing around with a delay line, using an MN3101 to drive it.  Pin 1 should go to the positive supply, Pin 3 is grounded.  Not when you mix up the positive supply!!!  I accidentally plugged Pin 1 into the NEGATIVE supply (by virtue of that lone red negative wire) and BAM!  The MN3101 exploded.  No mess like an exploded electrolytic cap, but the exploded chip was rendered useless nonetheless

Pics to follow!  Any other ?duh? exploding stories?

[Peter Snowberg]

OK, here's one.... My first DSP prototype in the late 80s. It was based around a production prototype of the Motorola DSP56001 which was a ***SCREAMING*** fast chip at the time. Motorola was selling them for the unbelievably special LOW price of $56 a piece.

I wired up all the Vdd and Vss lines to +5 and ground, except for one of the Vdd lines which I accidentally wired to +12 volts instead.  Instant mini space heater.

I've let the blue smoke out of more components than I like to admit to.

[puretube]

CD: I wouldn`t have expected that from you...
(and, yes: sometimes when I`m running out of wires, and have to use all potentials, signal and ground wired with one colour, it starts getting really "thrilling" on the breadboards...  ).

Peter: I prefer my cigarette or iron do the smoke @ the bench!

[MartyMart]

http://www.pbase.com/martymart/image/36531755

Here's a photo of when my Park practice amp went  BANG !!
The live wire fell onto the casing and I didn't spot it, i was just
changing out the pots and IC's   

Thats 240 volts folks  !!!

MM.

[cd]

CD: I wouldn`t have expected that from you...
(and, yes: sometimes when I`m running out of wires, and have to use all potentials, signal and ground wired with one colour, it starts getting really "thrilling" on the breadboards...  ).

Peter: I prefer my cigarette or iron do the smoke @ the bench!

LOL exploding things doesn't happen very often, BUT in my defense, I was out late the night before

Killing a $56 chip is a real kick in the teeth.  An MN3101 is no big loss by comparison, but I only have two (well, now one) which means sacrificing some other effect until I can get some more.

IIRC the most expensive part I've ever smoked was a $100 Celeron processor, but only because I was overclocking the crap out of it (that's a story for another board).

[Transmogrifox]

earlier this week I was experimentally making a voltage regulator with a couple transistors and a Zener for the next project on my breadboard--figured I better give it a fresh start with a well-regulated power supply.  I was using a 40 Volt DC wall-wart and regulating down to 9.4.  Well my danged Wavetek DMM told me that I was getting oscillations on the regulator and I was trying anything and everything for adding caps in certain places and making voltage regulator circuit changes to get rid of the oscillations...all with the 40 volt supply live.

In one evening I blew the face of 5 or 6 transistors and was watching plumes of smoke come pouring off from the breadboard, and roasted 4 Zeners when it fualted.  I had a good portion of my circuit that I'm experimenting with on the BB with a few LM319 comparators and some MC33078 op amps.  One of the times I had the regulator plugged into Vcc trace on the breadboard when it faulted and let 40 volts wide-open onto the circuit.

Fortunately, one of the MC33078's faulted first and protected the rest of the IC's from exceeding their maximums for more than an instant.  The comparators are OK.  I have a ramp generator running right now that has drifted by only 300 Hz on a 124 kHz signal in the last 30 min.  The opamps are acting right on bias conditions, and we'll see how the noise performance held up when I plug my guitar into it.

[CS Jones]

YES

Been there, done that too.

Red to +
Black to 0
Green to -

I've got to write it down and repeat it over and over again as I plug it in.

Top right box with the transformer on top.

[The Tone God]

I blown up a fair amount of stuff over the years. Mostly low cost things like a buck and under. I rarely fry something expensive.

An engineer I know, who has the nick name "fire marshal", was working at a company that made high end CCDs for digital cameras. One day he's walking by a group of engineers from another department who were celebrating and slapping themselves on the back for designing a couple of different chips that are impossible to destroy electronically. They covered every angle possible. So they lent out three of the chips for testing to see what kind of performance results they would get from the other department.

Fifteen minutes later he comes back with two blown chips and one that doesn't seem to work. He didn't try to fry them. He just used wired it up as per their schematics. Two of the chips were $60,000 a pop and the other was about $35,000. They don't know how he did it or what went wrong still to this day.

He still wonders why he got the nickname "fire marshal".

Andrew

[johngreene]

I've had my share of blowing things up. Most recently I was replacing the battery in a solar power electric fence driver and to see if it was working I connect my DVM to the output and flipped it on. Saw 1000V show on the display briefly and then it just  did the continuity tester beep continuously. Kind of like it flatlined.

My first tube amp I built was an AC30 clone and I had it all open on the living room floor trying to figure out where this hum was coming from. I made separate PC boards for the power supply, preamp, and output amp. The traces for the output from the tubes to the transformer where around 3/8" wide and probably 6 inches long each. But I only left maybe .1" of clearance between the trace and the ground plane. A friend was with me that had a Celestion Greenback someone gave to him and we were going to try it to see how it sounded. Turns out the speaker had a blown voice coil and when we didn't hear anything at first, I naturally turned up the volume. My friend then hit a cord on his LP and the output traces on the circuit board arced over and the arc travelled along all 6 inches of the traces before I could hit the power. It sounded like an arcwelder. We sat there with eyes as big as saucers as this white mushroom cloud of smoke slowly drifted up toward the ceiling. It was pretty cool.

--john