Hi everyone,
I have a Hameg 203-7 built in 1992, with a beam problem.
Documents and service manuals can be found here:
-
https://cdn.rohde-schwarz.com/hameg-archive/HM203-7_deutsch.pdf-
https://cdn.rohde-schwarz.com/hameg-archive/HM203-7_english.pdfBefore posting, I have been doing a fair amount of troubleshooting, including:
- I tested all high voltage CRT input pins with a high voltage probe,
- I traced the X1,Y1,X2,Y2 CRT input signals on another oscilloscope (i.e. after amplification, but I also tested the signal before amplification)
- I checked all the voltages, the sawtooth signal, tested the transistors (those in sockets) on a transistor tester, the blanking circuit, and many other things for almost 2 days
Conclusion: everything is fine !! Nice X sawtooth, blanking at the right time, Y voltage has the same shape as the input signal, Y1 and Y2 change accordingly in opposite direction, brightness and focus are ok, etc. But the beam jumps all other the place...
I just posted a video on yt so that you can have a look at the beam problem with the square calibration signal as an input on channel 1 :
https://youtu.be/X0FR12LhiH4If you have any idea I would be grateful.
For the moment, my conclusion is : dead CRT although I can't subscribe to this...
Thanks !