Problem Monaco GP

[councilface]

Hi all, I picked this up a little while ago now, but due to various reasons I hadn't been able to have a fiddle. For a 79er she's in reasonable nick and FPGAd. The only issue was a lack of red on the monitor. I thought this may be an adjustment issue so excitedly twiddled a few pots. Unfortunately I've messed up horizontal hold, and the screen now rolls continuously showing the below:


Does anyone have a schematic or manual for this monitor, I'm unsure what it is tbh:


I'd like to get the image back at least before I ask the monitor geniuses for assistance.

Thanks in advance,

CF