Raven Labs blender not working

[MrTea]

I picked up a Raven Labs blender/preamp in a job lot of pedals recently. It powers up in as much as the light comes on but I don’t get any signal through it. 

I had a friend take a look and he couldn’t work it out either. This was his diagnosis:

Unfortunately it looks like a power rail problem.  The voltage rails look good until it turns on, at which point the 18V split rail becomes an 8V single rail.  So I'm guessing something has blown.  I've taken all the chips out but it made no difference.

I know it’s a long shot to ask for help with such a vague diagnosis but does anyone have any ideas? Failing that, who in the UK would be well suited to look at fixing this? I’m in South Devon so someone local would be preferable but happy to send it off it it could be fixed. 

Many help much appreciated!