HP-35 Power Supply Waveforms

[cruff]

(04-10-2019 12:16 AM)albertofenini Wrote:  What do you think of the fact that Q1 with HFE equal to 1 or equal to 2 gives the same
behavior of a Q1 with HFE 16 ? couldn't this an HFE this low the reason ?
thx again !

A low hFE could certainly cause problems. It is possible there is sufficient base drive current available to make the low hFE transistors work well enough to regulate the circuit.