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Thread: Sunpak & Quantum: can tail wag dog?

  1. #1
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    Sunpak & Quantum: can tail wag dog?

    Trying to figure out best way to put together portable kit for outdoor lighting from the bits and pieces I have got and not sure what to do next?

    What I have is one good Quantum flash and Turbo battery that works fine, so that is half the problem solved.

    What I had was a Quantum QB1c battery pack that I was running with two old flashes taped together that did not work so fine, so I "lashed out" :-) and bought a Sunpak 611 that had been modified to run via Quantum cable from the QB1c Battery pack that should have worked fine. But when I go the flash and plugged it in to the battery pack the warning lights on the battery flashed a couple of times but nothing else happened. Replaced the cells in the QB1c but this did not help so took it to a repair guy who tells me the QB1c circuit board is fried. Not so good news. Now am not sure if the flash killed the the battery or if the circuit board was already fried. So, ask:

    Is there any way to test a flash to see if it has a short circuit before plugging it into a battery?

    Is it possible that if a flash has a short circuit it could fry the circuit board of a battery like the QB1c?
    Last edited by lowep; 25th May 2014 at 07:11.

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    Re: Sunpak & Quantum: can tail wag dog?

    Turns out the flash was fried! It did fry the QB1c! I did get the flash fixed by a backyard camera repair workshop in Mexico City who also tried to fix the QB1c but didnīt manage to do so. Instead I bought a replacement re-celled QB1+ from B&H in NY. So problem solved :-)

    In the process I found out Quantum batteries do come with an automatic switch off to prevent the battery being damaged from flash short-circuit or overload. But this was of no help in my case since - I found out later - some former owner had taken the liberty of rewiring my QB1c perhaps to fix some other problem and in doing so detoured around the auto switch off bit of the circuit board :-)

    So now everything works ok even though I got a good shake figuring out what the problem was and how to cure this old dog and replace the tail.

    :dh2:

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    Re: Sunpak & Quantum: can tail wag dog?

    Most electronic flashes contain electrolytic capacitors, which have a finite service life.
    They commonly fail shorted, which can damage other components in the flash.

    Even sitting unused they will deteriorate.

    I would never use one more than 20 years old. Even examples half that age have high failure rates.

    The only solution is to send the flash to a service shop that's familiar with them.

    - Leigh

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    Re: Sunpak & Quantum: can tail wag dog?

    I did as you suggest.

    The camera repair workshop in Mexico City replaced the capacitators. Thatīs how come it is working again.

    Unfortunately though they were not able to change the high voltage

    So now I am trying to figure out if it is safe to connect this old flash to my old Contax 645īs pc sync socket or if that will blow up the camera?

    Part of the problem is that I am also too old and my voltage is also too high not to mention my own fried circuit board that also needs replacing but that does not have much to do with this thread.

  5. #5
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    Re: Sunpak & Quantum: can tail wag dog?

    Looking into the question of old flash voltage comparability with 'modern' camera pc sync plugs, seems like there is no one-size-fits-all solution and the answer depends on the specific specs of the flash and the camera that is not very comforting, as such detailed specs as TCV for example for the Contax 645 are hard to come by and same goes for many other cameras.

    Here are a few relevant comments that I found on the internet while looking into this that give some idea of how different considerations such as trigger circuit voltage (TCV) and camera design effect how old flashes work with modern cameras. As usual many different opinions all to be taken with a grain of salt:

    "I use the Metz 45CT4 and 382 adaptor with my Contax 645 (for over 3 years) and have experienced no problems".... "I believe Metz do not recommend the 45CT1 on "modern" AF cameras". .. "You cannot use 45CT1 on current AF cameras only if the camera does not have x-sync terminal".... http://www.botzilla.com/photo/strobeVolts.html: Sunpak 611 TCV 4V reported by Kent Fulcher, but some old models Sunpak 611 will trigger at 190V, according to Tocad (via Jonas Lohr)".... "Canon usually lists 250V as the PC socket limit"... "It's likely you'll never see an official list of all Canon SLRs according to this specification"... "The trigger circuit voltage (TCV) rating for any EOS SLR is the same on the hot shoe as it is on the PC terminal (if the camera has one), but the acceptable TCV level varies according to the camera model...Incidentally, the main reason for the difference is the way the X-sync signal is generated. With the 250V cameras, the X-sync signal is generated electronically. With the 6V cameras, the X-sync signal is generated mechanically"... "the 20D can support a flash trigger voltage up to 250v (vs. 6v on the 10D and 300D) due to the use of a semiconductor switch rather than depending on a mechanical contact" ... "Damagingly high voltages still a possible problem with digital camera PC sync socket & old film era flashes"... "Was a very serious problem with early digital cameras. Later models have been raising their voltage protection levels. Some early Metz guns went over 300V. Later versions, sometimes of same model, reduced their voltages"... "Metz mecablitz 45 CT-1 units featuring a model number that is smaller than 534 000 are fitted with a so-called high-voltage ignition circuit. These flash units must not be directly connected to modern cameras as this could even damage the camera! All other flash units of the Metz mecablitz 45 CT and 45 CL series feature a low-voltage ignition circuit in keeping with the current standard...." etc etc etc....

    So probably wiser to avoid trying this unless know exactly how a specific flash will work or not with a specific camera, right, unless you are Benjamin Franklin.

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