I picked up this Vivitar Dedicated Thyrister 3000DT flash recently. It sprang to life with 4 AA batteries, and checking the hot shoe voltage it is 14 VDC. This is high for digital cameras—you try to stay under 12 VDC—but should work for some cameras if you don’t worry too much about their living or dying.
The really large problem to me is the lack of information on the “dedicated” part of the name. As far as I know there isn’t a camera brand that shortens to “DT”. DT must stand for Dedicated Thyrister, but Dedicated to what?
Some opinion suggests you can ignore the extra pins —other than the hotshoe center connector. I am not happy with that attitude, as messing with the cameras inputs/outputs on the accessory shoe could be disastrous!
On the other hand I may eventually find a camera that has the combination of pins this flash sports. Looking down on the flash’s foot all three extra pins are between the hot-shoe center pin and the rear edge. There are two spaced evenly on the right side and a third pin centered in line between the other two on the left side. Most pin arrangements I have seen work with some variant of four pin locations in a evenly spaced “box corners” arrangement. I have a Canon EOS Rebel S (film camera) that has all four extra pins in a box spacing.
It has been also suggested you simply discharge the flash before removing it from the accessory shoe, and only slide the flash on when it is uncharged. This way the chance of the hot center sync pin shorting out your camera’s other contacts is less likely.
All that aside this 3000DT zooms its head from Tele (85mm) through STD (50mm) to WIDE 1 (35mm) and Wide 2 (28mm). It has two auto settings (f/11 blue and f/5.6 red with ISO400 film and standard lens zoom position). It could have dedicated ranges and abilities in addition if the selector on the front is set to the white dot for the sensor on the flash being shut down.
On the back you can see the flash focal length settings at the top of the frame (above the calculator readings). You would set your film’s ISO, move down to the next strip and set it to T, S, W1 or W2 to see what your auto ranges would work over (for example the blue f/11 range would work between 1.3 and 5 m, the f/5.6 red range would be 2.3 to 10 m). Below that you have the auto check light on the left, the ready light on the right and the on/off switch in the middle. To check if you have enough range there is a open flash button on the back of the foot.
And this is where it turns nasty. Supposedly if you set the range to red or blue and fire the flash at point blank range (under 0.65 m) the flash should be pretty weak and the Auto Check light should glow something. Well this flash simply unloads at full power with no indication of any flicker of any light from the Auto Check.
So until I find—
a manual for this model of flash
a camera with the right pin arrangement
I won’t be able to tell if this flash is working as it should!
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