> Thanks Mr. Doepfer!
>
>
> Since I will have to remove the Supply/Interface Board to reach the DE's CEM3394, I assume I have to remove the 3.5mm
> jack screws on the top of the casing What's the proper tool to do so
>
>
> thanks so much and kind regards
> Frank

You need a suitable socket wrench (about 11 mm). Even pliers may be used but this increases the risk to damage the case and nuts.

Best wishes
Dieter Doepfer