I have finally started to fix/convert back my european Dragon's Lair.
It has been converted to JAMMA.  

 Luckily, most of the original wiring is still there, but obviously hacked up to use a JAMMA connector. I had some trouble finding the pinouts for the european board (is it any different from the US version?), but I managed to get most of it from studying the schematics.
Does anyone have a european (Atari) Dragon's Lair with original wiring? Can you please take pictures of the connectors to the boards, so I can be sure which cables go where?
For reference, this is what I read from the schematics:
1   UP   W/BK
2   DOWN   V/W
3   TEST   W/OR
4   +5   R/W+R/Y
5   LEFT   BU/W
6   RIGHT   GY
7
8   +5   R/W
9   COIN R   OR
10   COIN L   Y
11
12   COUNTERR BU
13   START 2   Y/R
14   START 1   W/R
15   ACTION   GN/W
16   5V RTN   R/GN
17   
18
19   COUNTERR V
20   GND   R/BU
21
22   GND   W
23   GND   W
24   GND   BK
25   GND   W
26   GND   W
27   GND   R/GN
28   GND   Y/BK
29   DISC AUDIO I/PB   BU
30   VOL.CONTROL W/Y
31   +25   W/BN
32
33   1 AUDIO O/P   OR
34   2 AUDIO O/p   BN
35   VOL.WIPER   R
36   DISC AUDIO I/PA   BK
J5
1   RED   Y/R
2   GND   BK
3   BLUE   Y/BU
4   SYNC   V/W
5
6   GREEN   Y/GN (KEY)