some time ago, this 3-channel PSU from Rohde & Schwarz appeared on my doorsteps.
It is a NGL 20 from around 1974. Every channel is capable of doing 0 to 20V and 0 to 600mA.
This is ideal for tinkering around with OpAmp circuits.
It is heavy for its size, the case is made of 1mm steel so very sturdy. Still, don't let it fall on your toes.
On some electrolytics a date code 12/69 was visible, so capacitor replacement time it is.
But now for the pictures (for a bigger size, right-click on the picture and open it in a new tab):
Front:
Right side:
Left side:
Back:
PCB:
Top view:
Electrolytics and driver transistors:
Driver transistor in detail (RCA 40409):
Other transistors are BC107 and BC177 so not the newest ones around.
Bridge rectifiers:
Front panel side of the PCB:
2N3055 backside:
2N3055 frontside:
Neuberger wobbly needle meters:
Binding posts and switch cabling:
Transformer, a bit dusty and crusty:
I have ordered the manual with the schematics for this PSU.
Will scan it and upload it here.
That's all for now, see you all next time!
