Problem in making a Ammeter using ADC 7107. (help please!)

Hi everyone!
I'm having a problem with ADC 7107 (haven't used before). i am trying to make a digital ammeter using this ADC. I have constructed whole circuit as shown there (link) but the problem i'm having is, the out of ADC is showing some random numbers on SSDs. They have told there to also calibrate it, like to maintain the reference voltage between pin35 & pin36 to 1volt by the 10k pot shown in the schematic, but i was not getting 1v. so what i did is, i took out the 15k resistor connected to the pot and even replaced the pot by 1k and got the 1v at these pins. but unfortunately, it has not resolved my problem and now the display is showing '1' at thousandth place (like '1...') and not sensing any current.

I have no idea where im doing it wrong. one thing that i observed, that IC 7660 for inverting voltage, is not giving a stable output and may be creating this problem?
other than that, im also using a 7805 which is giving me around 4.9v (7.5v dc input) and im using it without any smoothing capacitors, so also tell me should i use some capacitors?
thanks in advance.

https://electronics-diy.com/ICL7107_digital_ammeter.php

If you look at Intersil's website, they have an ordinary ICL7107 and a stable ICL7107S.
If you look at the datasheet of a 780x regulator then they show recommended capacitors.

so does it mean using an ordinary ICL7107 wont give an stable/proper output?
still surrounded by some confusions.
thanks btw.