Old PSU, further measurements
Today I did some more measurements on the old PSU, see results below.
At 16 Volts, without any load attached, this is what it produces (AC coupled). We see an ugly saw-tooth like voltage of about 80mV and a period of about 350uS.
At 16 Volts, under a 110mA load, this is what it produces (AC coupled). Now we have a ripple of about 30 – 40 mV.
Also, under 16V with a 1A load it did not produce more than ±35mV ripple.