Testing the working of the front shutter.


You would like to be sure if your precious bulbs are going to do their job when you want them to fire. Check if the control LED lights up 

First of all you have to know if your front lens shutter works properly. If you use the M bulbs you must be sure that your shutter will make contact some 20 milliseconds before the shutter is completely open. The bulb should bring it greatest power 20 milliseconds after ignition. The ignition finds place during the travel of the shutter on its way to open the shutter blades completely. Just before reaching that point, the contacts will ignition the bulb. 20 milliseconds later the shutter is completely open and the bulb is on its highest power. How do we know that this is going to happen. Just firing and watching the green test diode does not tell us whether the led lights up before or after passing the moment of full open shutter.

To be sure the contact finds place before the shutter is completely open, we have to set the shutter on "T" position. Now we release the shutter and the led lights up in a millisecond, but very good visible. As the shutter is still completely open, we know for sure that the ignition had taken place before the shutter closes again. If we set the shutter on "X" and repeat the same procedure, we do not see the led lights up. Thus the "X" setting is suppose to work just at the moment before the shutter is closing again. We can see that if we trip the shutter again to close. The led will light up immediately after the shutter is going to close. 

The electric circuit of the Speed Graphic


how to make it reliable.

The weak point in the electric wiring of the synchronization of the Speed Focal plane shutter is the connection between the build in release button and the inner connector sliding contact. The bulbs ignites when the focal plane shutter passes the electric contact on the right side of the housing. These contacts are intermitted by the build in release button to prevent the bulb going off when the focal plane shutter is wind up. However, the problem is that the inner and outer connector are hold together by a very poor construction. Sooner or later these contacts are going to oxidize and will interrupt the electric circuit. Soldering together the outer and inner contacts is the solution for perfect contact while using the focal plane shutter in combination with the Graflite. While soldering hold the jumper assembly on its place using the machine screw.



The moment the metal strip on the curtain slides along the contact spring fingers on the camera body it closes the electric circuit and fires the flash. You can make that visible by the LED plugged in the Extension outlet of the battery holder. The metal strip is integrated in the rubber covered fabric of the focal plane shutter. The red arrow indicate the metal strip. Note: The distance between the metal strip and the slit in the curtain. This is done to give the lamp the opportunity to peak when the slit travels along.

Make sure the plus and minus are well placed. A LED is a diode so the electricity can only go in one direction.

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