ktl wrote:
Finally solved it, 5 V supply was dead, due to a faulty filter cap.
Now it is working, but I guess that I need to do a complete check, what
I've seen is that the sweep starts one division below, then ramps up
very quickly, like within 1 to 2 subdivisions, and that there is some
sort of signal, even visible when inputs set for gnd.


Looks like there are even more of the voltages in the LV power supply
out of tolrance. Probably at least one more dry capacitor, or even
worse faults.


I'd recommend you download a complete service manual 8bama.sbc.edu or
bama.edebris.com) - you nee the Lizardtech browser to open the files,
but both (manual and browser are free of charge).

Then start to check the LV pwr supply carefully.

Looks like when you are through this, chances are good you have a nice
working scope.

hth,
Andreas