Soundcraft DCP100 PSU

Hi all, I have a Soundcraft DCP100 PSU that has developed a hum.
I am unable to find a schematic for it anywhere.
The problem is R5 has burnt out and is black so I cant identify its value.
It runs in parallel with a small cap between chassis ground and 0v.
If anyone has the schematic, or can have a peek inside one that they own or can suggest a suitable value for this location I would be most grateful.
Thanks,
bce