ICL 7660 S

[dromilious]

Hello my friends.

I have a big problem with ICL 7660 S .I bought about 50 pieces from different sellers .Only 10 of them are good for audio purpose.
The other make the common annoying noise.BUT the good 7660S when i use them as voltage inverter they burn .The others with the noise don't burn .What is happening ?

[italianguy63]

Make sure you have pins 1 and 8 connected together.. that is the frequency boost to avoid whine.

As for "burning" I don't know what you mean... If they are getting hot... they shouldn't.

What voltage? and you should post your circuit.

MC

[dromilious]

The circuit is a fuzz face based one with russian germanium transistors. 9volts supply of course.When i plug the dc after 1 second gets hot and smells burnt and of course damaged.

[idy]

Sounds like a short or near-short. Power disconnected, measure resistance between power "rails," here the ground and output of the 7660. Trickier but more precise is to measure the current the circuit is drawing.... this means lifting a leg or otherwise disconnecting the power rail as it is a "series" measurement. If we know what you are doing someone can explain how.
Probably just look for shorts!

[dromilious]

The pain in the head continues.I bought also some max1044 .I use them for a keeley katana based circuit for voltage doubler .Again all of the 7660s squeeze and the 1044s also. I dont know what to do !

[Rob Strand]

9volts supply of course.

Is that what you actually measure with a multimeter?

If you are using a DC plug pack the voltage could be much higher.
https://www.diystompboxes.com/smfforum/index.php?topic=122986.0

IIRC, more than 12V will blow a 7660s.

[italianguy63]

[BluffChill]

I've also had problems with 7660s chips. They whine for me too. I'm going to double check I have pins 1 and 8 connected.  From a previous post:

I've also had problems with the MAX1044/7660s chips.

I had a few batches of these from various suppliers. I've noticed with the 7660s in particular, there are two variations:

- 7660S CPAZ V15084P
- 7660S CPAZ V15284P

the V15284P version of this SQUEALS LIKE A PIG even in True Bypass. I played a live show with one once and there was a constant high pitched oscillator noise in the background which we traced to the Gristleizer. I popped it out and put a 15084P in it instead and the noise is gone now. Unfortunately, I have previously fried a couple of these for no apparent reason in the Gristleizer. No idea why. You can't win.