[LargeFormat] Cable release for Prontor shutters?

[Joe Tait]

I got a 480 APO-Ronar mounted in a Prontor Professional 3 shutter that I
have been unable to find the "central remote control" unit for. For those
unaware, that is an accessory used to control the aperture & shutter release
of these self-cocking shutters.

Does anyone know of a substitute for it, or an adequate cable release to
trip the shutter. It is extremely heavy-duty and I can't find a cable
release that trips it all the way.

Thanks.

-Joe