STFM C070789 Rev.f video problems.

[Bigted1977]

Ive recently picked up this stfm with the C070789-001 ref.f board.
I have discovered that there is not a lot of info on these boards.
To add insult to injury ive been and blown the bank on a Rigol ds1054z as it will help with projects in the future. I dont have much of an idea what im doing with it to be honest, i hope to learn as i go along.

Things I have tested/ discovered.

when i power on i have no output to the screen via a scart from retro computer shack (that works ok on my ste) or via the rf plug, it does change from static fuzz to black screen when powered.

The floppy drive can be heard to be working, I downloaded a demo disc, and ran the file on an e,ulator at the same time as the st was booting and the drive pauses were the same so in my eyes its loading the program as the emulator.

no video and no sound.

Have removed the glue and mmu chips cleaned and reseated no difference.

when i plugged the monochrome st monitor in it seems to be over volting, again ok on the STE.

The clock circuits all seem to be present and correct.

I get 15.6 Sync signal on pin 2 of the 1377.

what should i test next and is there a schematic for the video system ?

Ted