Hello All,
     I am trying to build a voltmeter using the ICL7107 ADC chip. Here=20
is the URL of the schematic that I am using. I did not use the circuit=20
on the left side that controls the individual LEDs. I am using a ICL7660=20
DC-DC converter to generate the -5 volts. I can adjust the reference=20
voltage to 100 mv and the display initializes on start up and then it=20
shows 1 or -1 with a flashing - sign. If I press the test switch the=20
display shows -1888 like it is supposed to. If I ground the + lead the=20
display almost goes to zero. When I disconnect the plus lead and leave=20
it floating the display slowly climbs in value until it overflows. I=20
know that this is an important clue but I can't find the problem.
     I have also tried three different circuits including the one that=20
is in the datasheet and I have tried two different chips. The + and - 5=20
volts are ok, the ground is good, and the clock frequency is 66KHz.
Could someone please help me?
Thanks,
rich!
Sorry,
	Here is the URL:=20
http://www.electronics-circuits.com/tech/wp-content/uploads/2012/10/del2000=
9.png=20

It is late. I'll try the other suggestion sometime tomorrow.
Thanks,
rich!
--=20
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