I tried LCF meter capacitor.
At start, with no capacitor connected, the frequency is approximately 330.000Hz and 987pF displayed on second line.
If I measure a capacitor value seems to look pretty good (I did not calibration) but when I remove that capacitor or press the SET, either of the two actions makes them aces, the display shows a frequency of over 15MHz and displayed 2-3 pF value of the bottom row.
I changed the resistance R5 4.7Ko but without success. I shorted R5 and then all phenomena gone but the display frequency is different than that which could be measured with the meter at the entrance CLK/RB6 (pin 12).
I used only indicated components, HEF4011BP, PIC12F628 (not A) ...
Do you have any idea how to solve the problem?
Thank you.