Help with resurrecting an analog scope

[pitpat]

Hi, im not super good with english so be kind.
I got for these quarantine days a cheap Hameg 103 to be restored.
I'm quite new with old school tech, anyways the thing is when i first got it everything look'd ok but after a few minutes of playing with the test trace all went black (or white since we are talking about crt  ).
The strange thing is that the component tester is working good, vertical line for short-circuit and L-shaped line for diodes.
After replacing some caps that wasn't quite in specs anymore (only the few that i had laying around) in normal mode i got a dot that i can move with the x-y position knob.
The big resistors of the y final amp gets really toasty.
Since the component tester isolate the y-preamp board i would say that the fault can be located in there.
What do you guys think?
i'll leave the service manual for reference https://cdn.rohde-schwarz.com/hameg-archive/HM103_englisch.pdf
Thanks.