ICL 7107 digital voltmeter helps needed

Thread Starter


Joined Jun 26, 2012

I'm building ICL 7107 digital voltmeter with 200mV full scale as Figure 12 (page 11) on http://www.intersil.com/data/fn/fn3082.pdf
Here is the problem I'm facing:
it shows random numbers, sometimes showing 1666, and it has no effects even when I try to calibrate by adjusting the potentiometer or shorting the inputs pins the values remain the same. Even the whole potentiometer is removed the value still stay there!
I have read through the datasheet and couldn't find any possible defects of the components that might have caused this.:confused:
I have tried to replace the 0.1 microfarad capacitor with 1 microfarad but the problem remains the same and I did check the connection trace.
So, I was wondering if you have any idea? and Thanks in advance, that really means a lot to me. :)



Joined Dec 29, 2010
Take a picture of your circuit board or breadboard. May be we can help you spot the problems.

Last edited:


Joined Jan 23, 2011
Hello William,

I think also, that you have a dead IC.

These ICs are very sensitive to static electricity. :mad:

Normaly I don't care against static electricity to MOS-ICs, but after killing two of this voltmeter and counter ICs I really take care of proper handling and grounding during installation. :rolleyes:



PS: Sorry, if my English is not so good.