Need some help: smoke and sparks from my 555 chip... oi.

No_6 · Post by **No_6** » Sun May 03, 2009 9:45 pm

I followed the instructions on this page: http://www.geocities.com/SiliconValley/2072/proj2.htm

The LED I hooked up lit, but did not blink. I ran 5v to the chip, and within a second had smoke and popping sounds coming from it.

Clearly I did something wrong. Well, lots of stuff.

Here's what I did:
I did NOT use a circuitboard, instead 'extending' the pins by soldering an inch of wire to each.
I connected the power directly to the #8 and #4 pins. I connected the resistors to the ends of the wires I soldered on (one all the way to the outside of the #8 and #7 wires, and the resitor to #7 and #6 inboard of that). The capacitor was wired inboard both resistors. I hooked the + lead of the LED to the #3 and put another resistor between the - lead and the ground #1 pin. I taped the pins to make sure that none of them were touching despite the solder and extra wire.

Anyone have any ideas why it fried?

I could take a picture, but it really is a mess. I did it this way because my circuitboards haven't arrived yet and I wanted to see if I could follow basic instructions. Clearly I can't.

So when I do get my boards in, I'm hoping not to fry everything. I have a bunch of 4060 chips ready to go. I may order a bunch of 555s as well for their smaller size.

jwrjr · Post by **jwrjr** » Sun May 03, 2009 10:31 pm

Are you sure that you didn't have the positive and negative power supply connections reversed?

No_6 · Post by **No_6** » Sun May 03, 2009 10:32 pm

I'm not positive. The chip didn't have the little cut-out, so I had to guess from the orientation of the printing. That's what I get for buying Radio Shack...

Thrusterhead Jones · Post by **Thrusterhead Jones** » Wed May 06, 2009 5:27 pm

Its possible that you had leads or wires touching (shorting). Fortunately 555 chips are dirt cheap. And if you insist on buying from Radio Schmuck get yourself a solderless breadboard on which you can build you circuit, modify it, and smoke check it before you goe through the hassle of building the real thing and watching it fail the first time you power it up.

Also, if your power supply doesn't have one, install an in-line fuse.

No_6 · Post by **No_6** » Thu May 07, 2009 2:19 am

Cool, thanks. Breadboards are on the way as are 10 555 chips. I do like how they are half the size of the 4060, and as space is now at a premium in my primary hull...

Thrusterhead Jones · Post by **Thrusterhead Jones** » Thu May 07, 2009 5:58 pm

The breadboard I was refering to is the white plastic type where you plug in your parts and jumper wires to test your circuit. Not intended for actual use in your model.

You want to use in you model is the fiberglass type with the grid pattern of .10 spaced holes, copper pads and power/ground traces.

No_6 · Post by **No_6** » Thu May 07, 2009 7:46 pm

Ahhhhh! I'll have to order one of those.

Ordered. Probably be here in three weeks. It's coming from Hong Kong.

USS Atlantis · Post by **USS Atlantis** » Thu May 07, 2009 7:53 pm

No_6 wrote:Ahhhhh! I'll have to order one of those.

Picture of what one looks like with components on it for reference

Bussard Test

No_6 · Post by **No_6** » Thu May 07, 2009 8:40 pm

That makes my head hurt... thanks for the pic!

You wouldn't have a pic for just the Nav lights, would you?

USS Atlantis · Post by **USS Atlantis** » Fri May 08, 2009 5:12 am

No_6 wrote:That makes my head hurt... thanks for the pic!

You wouldn't have a pic for just the Nav lights, would you?

Unfortunately not - didn't take a shot of the breadboard when I was testing the Nav Beacons