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10-11-2010, 04:44 AM   #1
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Topman Thyristor 230B flash 1980's, safe on Kx?

I got this flash with my K1000 in the early 80's. Can anyone tell me if I will be able to use it on my Kx, without doing any damage to the Kx? I've looked all over the internet, but could not find any specifications for it, like V etc.
Thanks in advance
Christo

10-11-2010, 02:56 PM   #2
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What you need to know is the trigger voltage of the flash. If it is over 10v, you might damage the camera's circuitry.
10-11-2010, 11:02 PM   #3
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Thanks, that is what I am trying to find out. Will I get info somewhere on the inside, if I decide to strip it?
Christo
10-11-2010, 11:39 PM   #4
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No need to open it up.

Put batteries in, turn it on and wait for it to charge up (Ready Light on).

Use a digital multi-meter, measure the voltage between the center pin and the terminal on the side of the hot foot (visible in photo #2 in your post). That's the trigger voltage.

If the center pin is positive and if the voltage is less than T (plug in your number here) volts, the flash is OK to use.

To me, T is 24. Don't ask me where I got it from.

10-11-2010, 11:52 PM   #5
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Thanks, I'll try that
10-12-2010, 12:13 AM   #6
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Hi SOldBear
I measured it, with a friends meter. If you put the red wire on the centre pin and the black one where you said, with the meter on DCV 20, I get a reading of about 3.4. The flash uses 4x1.5v AA batteries. So from what you said, I should be safe?
10-12-2010, 01:52 AM   #7
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That thing looks old and cheap, so I wouldn't take a chance regardless of the voltage.
10-12-2010, 03:02 AM   #8
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Ira, as I said it is about 30 years old. "Cheap"? I can not remember the price when I bought it, but with the Rand/$ exchange rate about 7/1, I would like to make sure before I trash it. I do not mind using old stuff, as long as it works and do not damage my new camera. I tried a few shots in Tv, with shutter speed at 1/60 as it was supposed to be used with my K1000, and they look ok to me. Camera is also still working, but it would be nice if I can get some definate yes or no on continous usage of the flash.
Thanks

10-12-2010, 11:39 AM - 1 Like   #9
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QuoteOriginally posted by altopiet Quote
If you put the red wire on the centre pin and the black one where you said, with the meter on DCV 20, I get a reading of about 3.4. The flash uses 4x1.5v AA batteries. So from what you said, I should be safe?
Yes. It sounds safe to me. I would use it.

The trigger voltage has nothing to do with the batteries. Some of my flash units (Metz CT45-1 for example) has trigger voltage of about 200V. I added a little "voltage reducing" circuit to bring it down to 7.5V.

Like you, I see nothing wrong using old stuffs. I have 2 Pentax 540 units, but I probably use the old flash guns more. In addition to what listed in my signature, I have (and am currently using off and on) a Pentax 160, 200T, Vivitar 5600, Sunpak 522, Albinar (can't remember the model #).

Last edited by SOldBear; 10-12-2010 at 11:45 AM.
10-12-2010, 09:56 PM   #10
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Thanks again for your time, and advise
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