Hi Peter,
Hi Thilo,
Congrats on the progress!
Thanks!
That is a gorgeous CRT display, with flat face, sharp and undistorted drawing for a 7cm tube!
And battery powered too!
Definitely a keeper!
Careful in the X-Y-mode with the intensity, do not burn in the screen!
Undistorted? Not so much.
There is quite some "pillow" distortion. But it's not too bad.
I know about screen burn. Won't leave it running too long.
...weed out all the Ge transistors, replace them with Si ones.
Looks like there are only in the HV generator, RFT has already redesigned that, and in the linear PS circuits.
Those in the PS are non-critical, replacement should not pose any trouble, just readjust the trimmer pots.
But if you keep it stock, that is understandable too!
This unit is built according to the 1970 schematic. So basically, there's no silicon inside.
All Ge.
I've swapped the transverter transistors with near-original GD241C, which works fine.
But I won't go through all the transistors, unless necessary.
Feedback from the service guys is, that they are fine.
So what is left to do?
Regards, Peter
Current To-Do-List:
Repairs:
- Rough adjustments -Done-
- Take care of trigger problems with faster timebases (see pictures; 500 us/cm vs 100us/cm)
I don't yet understand where the trigger is formed. I'll have to do more research here.
Maybe I'm doing it wrong; but maybe the trigger is wonky in those timebases.
- At a later stage: Swap the potentiometers. Some are quite crusty, but work fine.
- Put back the banana plug assembly for the battery box. Won't ever use it, but it's nice to have everything restored, although invisible inside the unit.
Cosmetics:
- Clean front panel, knobs and screen assembly -Done-
- Swap out BNCs for new ones (this might be another larger operation due to the construction) -Done-
Operation:
- Understand proper operation (which is quite different from Tek or other scopes)
- Get a decent function generator for adjustments and thorough testing.
Is it a keeper?
Absolutely!
Was it worth my time and the components?
Absolutely!
It's a vintage scope built in former GDR and a piece of history in itself.
Thus, it's easily a few years older than I am myself.
It works just fine for visualization of traces. Also it's a nice addendum to my Sony-Tektronix 314, which is roughly the same vintage, but amazingly different in function and controls.
It's not a precision measurement device and no "daily drive". But that's what I have my Voltcraft/Hantek DSO-1062D for. So no worries here.
So once again: Thank you very much for your help, guys!
Wouldn't have made it without your support!