Gould Advance OS 4100 Oscilloscope

Hi all, I'm looking for someone who has experience repairing Gould oscilloscopes.

Some time ago my OS4100 started giving me problems, the tracks started to fade until they disappeared completely. After an initial check I realized that the diodes of the voltage multiplier were damaged together with the capacitors of the power supply and the MJE3055 transistor of the oscillator. Once everything was replaced it started working again but it only displays one point on the screen and when you move the various time switches it doesn't change. Despite the service manual I'm still at a standstill. Can anyone give me some advice? A thousand thanks