Pastyface 12v zener diode question

[Philthy]

Just doing some trouble shooting....

I've just realized I've used a 9v zener instead of the 12v specified.

Would this make any difference to the operation of the voltage inverting IC? I'm reading 3v on pin 3 when it should be 0v right?

thanks

[Halotem]

Yes it will, you should be carefull while projecting zener diode voltage regulator (https://911electronic.com/zener-diode/)

[mauman]

Just doing some trouble shooting....

I've just realized I've used a 9v zener instead of the 12v specified.

Would this make any difference to the operation of the voltage inverting IC? I'm reading 3v on pin 3 when it should be 0v right?

Your 9V zener will start conducting somewhere around 9V, maybe a little more, maybe a little less.  Your battery or power supply is probably a bit over 9V, so the zener will be in constant conduction to ground, trying to keep the voltage at 9V or below.  It's supposed to protect the DC/DC converter if you apply more than 9V, and only conduct to ground in an emergency, so 11V or 12V is the best value for the zener here. 

Pin 3 should be ground, yes.