Here is another update about this NGB 32 / 10 from Rohde & Schwarz.
Today I wanted to adjust and calibrate it but then I discovered a strange thing:
while trying to set the voltage output at zero to 0V I've found, that I have an output
of -0.6V and it doesn't change while tweaking the related trimpots.
What?
Checked again the schematics and found another dead transistor (T16, BC107B).
Replaced it and his colleague (T7, BC177B) and then I was able to set the
output voltage for the zero point to 0V.
Then I adjusted the maximum output voltage to 35V.
Next part was adjusting I
min and I
max for the CC mode.
That was easy. Set I
min to 1mA (manual recommends something below 20mA) and I
max to 10A.
The last part was adjusting the switching points for the relays between the transformer and the
rectifier. They switch between different tappings of the transformer to reduce the dissipation power
of the output power transistors.
Switching points are set at 16V and 27V.
Done.
Now I need to test this thing.
Hmmmm....
I have this nice russian vacuum tube, the GU-81M. This tube needs for the heating 10A at 12.6V. Perfect!
And here we go:
Overview
The frontside of the NGB 32 / 10
And a nice glowing tube
Thank you for watching.