Hameg Oscilloscope HM1004-3 Timebase problem

[AwaisN]

Hi,

I have Hameg Oscilloscope HM1004-3 which was working fine. Now it is giving timebase problem. Timebase horizontal line is not appearing in measurement mode but horizontal line is clearly visible in Component Tester mode. Few weeks back I opened and clean it, at that time timebase line was restored but now the fault appeared again. Information texts are ok on the screen.

I need help to troubleshoot this fault and specific service manual of this model. I found service manual of HM1004 from the below link but PSU board is little bit different from the manual.

https://www.scribd.com/document/381437371/Hameg-1004-1004-3-Oscilloscope-Calibration-Manual-Board-layout

Thanks and regards,
Awais

PS: The photo was taken before cleaning.