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Old May 12, 2006, 8:56 PM   #1
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I bought three Sunpaks on ebay: 144, 422 (for Pentax) and 433 (for Minolta). The 422 and 433 have three pins on the bottom where the 144 has only one. I also bought three slave/hotshoe pairs: "Sonia" hotshoes and Sonia slave modules).

I tested the slave pairs on the 144 and it flashed as it should when I shot another flash at it. However, I can't get the 422 or the 433 to fire with the same slave pairs mounted.

For the 433: I cut the two 'extra' wires that I assume are intended for dedicated operations that I don't need. The flash fires from the test button, it fires when I short the active pin to the ground connection, and it fires when I attach the Sonia hot shoe and short out the PC connector. But the slave will not fire the flash.

For the 422: I have not cut any wires. Without a hot shoe attached, the test button fires the flash as does shorting the hot pin to the ground. With the hot shoe attached, it will *not* fire from the test button and will *not* fire when shorting out the hot shoe. I'm guessing the dedicated circuits are interfering because their pins are shorted out in the hot shoe. And of course the slave won't fire it either.

Does anyone know what's going on here?

-- Chuck
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Old May 13, 2006, 10:34 AM   #2
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Hey Chuck... I'm no expert on strobes. So, perhaps someone that knows a lot more than I do will respond.

But, you might want to try taping over the extra contacts so that they're not shorted out.

Some people actually remove them. See the posts in this thread as an example:

http://www.stevesforums.com/forums/v...mp;forum_id=84

Don't you have a KM 5D? I see a post suggesting firmware updates for it you made.

If so, be advised that a slave trigger that's not "Digital Aware" will fire too early if you're trying to use the camera's built in flash to trigger it, resulting in underexposure.

That's because the built in flash on the 5D will always use a preflash. So, the slave triggers see the preflash and fire with it, before the shutter is open for the main flash that follows. There are some digital aware slave triggers available that can ignore preflashes.

If you use a hotshoe attached flash via a Minolta FS1100 or equivalent adapter to give the 5D an ISO standard hotshoe, then you can use a small flash to trigger optical slaves that are not digital aware.

I've got a 3rd party adapter that gives my 5D both an ISO standard hotshoe and a PC Sync Port. If you search for FS-1100 on Ebay, there is a vendor in Hong Kong that usually has multiple listings for these third party adapters. Here is one of them (it's the same one I've got):

http://cgi.ebay.com/ws/eBayISAPI.dll...m=170000219364

But, be advised that the FS-1100 does not have voltage protection built in. So, it's probably best to limit the trigger voltage to around 6 volts. Ditto for the third party adapter like I'm using (no voltage protection).

The Minolta PCT-100 does have voltage protection built in to give the 5D a PC Sync Port, so it's safe to use PC Cord attached strobes with trigger voltages up to 400 volts with it (but it doesn't give you a hotshoe).

Edit/Added:

OK -- looking by through the old posts on this subject, I guess you're already aware of the adapters, preflash, etc. My memory isn't what it used to be. ;-)

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Old May 13, 2006, 4:29 PM   #3
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JimC wrote, "My memory isn't what it used to be. ;-)" And you can add my eyes to that list too. But, I'm not even testing these strobes on a camera. I'm just firing on the test button on any old flash, trying to get the Sunpaks to fire from a slave connection, and only the 144 works. If I ever get them to work, I will use an external flash on the 5D as the master flash, not the built in one.

It will be possible to fire the outboard flashes from a PC cord connection, but that limits their positioning so I *really* want these slaves to work.


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Old May 17, 2006, 7:30 AM   #4
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cgbraggjr wrote:
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For the 433: I cut the two 'extra' wires that I assume are intended for dedicated operations that I don't need. The flash fires from the test button, it fires when I short the active pin to the ground connection, and it fires when I attach the Sonia hot shoe and short out the PC connector. But the slave will not fire the flash.
This means the Sonia (I understand that it's a kind of slave cell, isn't it?) internal resistance is to low (cheap SRC ?) and trigger the flash as soon as it touch the pin; after the flash fired, the Sonia keep the flash in low ("shorted"), so it won't recharge and be able to fire again, until you dismount (disconect) them apart.



cgbraggjr wrote:
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I'm guessing the dedicated circuits are interfering because their pins are shorted out in the hot shoe. And of course the slave won't fire it either.


Possible, one of the dedicated pins must be a flash cut of signal pin, so it can keep the flash from firing and recharging.
Isulate those pin with a plastic sheet if you don't want to alter the internal wires.


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Old May 21, 2006, 3:16 AM   #5
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Kcan wrote, "This means the Sonia (I understand that it's a kind of slave cell, isn't it?) internal resistance is to low (cheap SRC ?) and trigger the flash as soon as it touch the pin; after the flash fired, the Sonia keep the flash in low ("shorted"), so it won't recharge and be able to fire again, until you dismount (disconect) them apart."

I think you misunderstood me. I shorted the bare connector on the hot shoe with a safety pin, proving the circuit works, but after I connected the slave the slave would never fire *this* flash. If the resistance in the slave is too low it's only for some flashes; it fires a Sunpak 333 (not dedicated to any one camera) just fine.
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