Need some help. Having chip failures

[loogie]

I have a friend whose been working on this simple LED pulsing curcuit:

http://www.electronics-lab.com/projects/motor_light/020/

When he uses a battery as the power source it works ok.  When he substitues a 4.5v wall wart it goes for a while and then the chip fails.  He's tried adding some resistance to the power supply and that seems to help, but it still eventually fails.  He needs it for a display he's working on that will be running for hours at a time.

Do any of you have any ideas on how this could be improved or how he might be able to save the chip?  I know I'm not giving much info, but he's in England, I'm in Akron and neither of us knows too much about this stuff.

Thanks

[sluckey]

Be sure the wallwart is DC. Then put a 7805 5 volt regulator (with cap on input and cap on output) between the wallwart output and the circuit.

[loogie]

Thanks!  I'll pass that along.

[PRR]

Try TL072 chip.

Try 100K resistor so that huge cap doesn't blast the chip's input.

But circuits like this DO usually work, without special care. You are nowhere near the chip's 32V supply voltage limit, output current, etc. And a circuit very much like this is on the first page of the '358 datasheet.

[PRR]

I'm now thinking: bad connection, makes contact at first, then fails; the act of swearing and replacing the chp "fixes" it, at first, then fails again.

Stuff like that makes us crazy.

[loogie]

Try TL072 chip.

Wll do, guv'.  Thanks.

[sluckey]

If all you want to do is flash a LED and you're not locked in on any particular circuit, you should look at the 555 timer. Very simple, cheap, minimum components, and rugged.

[loogie]

Is the 555 capable of a ramp wave?  Thats what we need.

[sluckey]

no.

[loogie]

This is an international project.  My good buddy, Heywood, down in Tejas had success with an LM324.  I'm guessing he used that because that's what he had.

I'm going for the TL072 this weekend.

[DummyLoad]

no.

yes.

http://www.allaboutcircuits.com/vol_6/chpt_6/8.html

[loogie]

Ok, looks like another option.  Thanks!