Korg Poly800/EX800 Users

Hi you all, maybe someone could lend a hand here.

    I have an old EX-800 which I want to revive. It was connected to a 220V 
mains, blowing something inside. I got it already messed, but not that much. 
Seems 3 transistors were changed, and a zener. But the transistors are not 
original and the zener is unreadable. Also, the only schematic I got access 
is incomplete and very hard to read.

    So, if anyone is willing to open up his/her gear and take a look, I 
need:
    - What zener is D4? Can you read the tension between its legs?
    - What tr is Q4? Is it really inverted on the board?
    - Taking a look at schematic, what are the tensions on the points A 
(should be +5), D (should be +5), 6-7m 6-8A (should be -5V), 6-9A
    - Is there any documented mod for changing the internal power supply for 
a +/- 5V one (I think there is also 12V)?

    Thanks!
    Alexandre