Compur Shutter Repair: Which tool needed for screw 304 in Synchro Compur 1 MX

Hi,

I'd like to take apart a Synchro Compur 1 MX shutter (from a 150mm symmar) but I can't open screw 304. It has two slots at both sides of the pin in the middle. The screw drivers which I have for two slots all do not fit. Does anybody know which tool will work for this screw in this shutter?

Thanks

Andreas


The technical drwing can be seen here:

http://www.suaudeau.eu/memo/rep/compur-repair/04-43.jpg

A similar or the identical screw is visible in the second photo here at 4 o'clock:

http://images.google.de/imgres?imgur...-ECa0Q9QEILDAC

That is a tough screw to get out. If you have a screwdriver that's too thick for the screw you can probably get away with filling it down until it fits. That worked for me in the past.

For these i've used small needlenose pliers, or a small, cheap adjustable lens retaining ring removal caliper, ground down to size if needed