Wanted: Service info for Rhode & Schwarz NGRE 40/30 PSU

[PM3295]

Friends,

I recently bought some hefty R&S PSUs on auction. One, an NGPU 70/20 and the other an NGRE 40/30.

I managed to find a diagram for the NGPU 70/20 online and repaired it successfully. With the later model, however, I am unable to find any information, not even a brochure or operating manual. This is quite surprising since the last unit looks more modern with digital displays. It is also confusing as the unit looks almost completely solid state based, until I spotted a lonely valve (Siemens 85A2)! This appears to be a reference tube. I suppose there were no accurate zeners available in the 85V range at the time?

It is possible that this sold mainly in Europe as it is permanently wired for 250VAC/ 50 Hz operation. There are no tappings on the main transformers to strap it for 110VAC.

If anyone could help with a diagram for this unit, I would greatly appreciate it.

Thanks