WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
Getting no numbers there must something bad with the IC`S. just try what i wrote last thread to confirm these parts are working. Test all two displays at same time with all the numbers 0 till 9.