Why my reproduction of DOD 250 does not work?

[rikk]

for duck_arse: the DC voltage on the pins 7 and 4 of the IC is 9 volt (as expected).

I'm not sure if duck-arse expected 9V on pin 4..

I meant that the potential difference between 7 (+) and 4 (-) is 9V

duck_arse understood what was meant by 9V. but with an IC having 8 pins, we expect 8 voltage readings. and we don't want potential differences, we just want your black meter probe on ground/0V/earth, and the red probes and reads the pins. thank you for your attention (if applicable).

I see, here all measures for each pin:
1. 0V
2. 4.4V
3. 3.1V
4. 0V
5. 0V
6. 4.31V
7. 9.6V
8. 0V

These are the numbers of the pins that I have followed:

[Chillums]

Honestly I would take it all apart and start from scratch.  Also, cheap resistors and cheap 4148 diodes don't work well in breadboards because the leeds are too thin.  Hard to tell by the picture.  Try sticking a cut off from a resistor leed in the same hole of anything that looks super thin to give it a better connection.  Did you do a continuity check of all of the connections?  That should also help.  Don't give up!!! And welcome to the forum!!!

[antonis]

I see, here all measures for each pin:
1. 0V
2. 4.4V
3. 3.1V
4. 0V
5. 0V
6. 4.31V
7. 9.6V
8. 0V

These are the numbers of the pins that I have followed:

DC (I presume..) measurements are fine..
(although pin 6 & should be identical..)
pin 3 low measurement is probably due to DMM loading..

Taking into account that Pots are working, as stated earlier, check for proper R8(1M) and R7(4k7) values..
(even with diodes out of circuit, your build should distort for signals of greater than 20mV amplitude..)