I have a Speed Graphic in which the cable appears to have broken, or become disconnected, at the shutter release pushbutton terminal. Should the cable be replaced? And what is the best procedure to install it. Should I seek professional help, or is it easier than it looks?
Also, I think I may have a 'Pacemaker' model, but it doesn't say on the camera; how can you tell?
My expertise is electronics (old and new), so please excuse my newbie questions.

If you have a large button on the lower right side and the lensboard is metal not wood, then you have a Pacemaker model.

You say it's a Speed not a Crown, in which case the body lever does double duty. I never use that release for the front shutter but it works well for the back shutter. Make sure the vertical slide lever on the side of the camera is in the "back" position, you have to push it in to move it. Then try again. I wouldn't bother trying to use it for the front shutter, use a cable release instead.

Download the factory Top Rangefinder Service manual @ http://www.southbristolviews.com/

Thanks for the help.