(Almost) shot dead by my flash

[TheFlyingCamera]

The flash I use the most (2400 w/s pack) thank heaven has a built-in discharge system when you turn it off. That said, I still would never want to even contemplate opening the case on it. If you think what a Vivitar 283 can do, well, imagine 2400 w/s worth of jolt discharging across your body. Can we say barbecue? That's one I will ALWAYS leave to a professional.

 

[Worker 11811]

while I certainly agree that it is important to respect these devices, fear for lack of understanding isn't going to do anybody any good.

Yes, a hit from one of those caps will make your eyes light up like a pinball machine. Trust me. I know. I've been bit by them a time or two. It doesn't tickle.
However, we should not treat them like ticking time bombs. If you understand what they do, how they work and how to handle them it is possible to experiment with them and be perfectly safe.

While I do not advocate that people take apart their flash guns and root around inside there with their fingers, I would certainly encourage somebody who has the will to learn and who has respect for what he's dealing with to investigate the inner workings of a flash that no longer works or is no longer needed. Just learn what the components are and how to identify them. Just about any good book on electronics that you can find in the library will teach you what you need to know.

This ain't black magic. Just be careful.

 

[brucemuir]

I really don't want to know, what a professional flash with several times that power can do. If you have a weak heart, these things can short you out. Seriously. Don't touch anything electronic, unless you're 100% sure of what you're doing.

That's why the Norman's were/are known as "widowmakers"
If you even change the power at the pack while the capacitor is charging... watch out!

 

[olleorama]

I have modded several flashes and built my own HV-pack (based on TL-494) and had a few accidents. But I'm so goddamn tough that when the flash tried to electrocute me, it jumped! GET SOME!

 

[MattKing]

If you understand what they do, how they work and how to handle them it is possible to experiment with them and be perfectly safe.
This ain't black magic. Just be careful.

You could say the same thing about most automobiles

 

[Worker 11811]

Much agreed!

People will sit in a car, just two feet away from ten gallons of highly flammable and potentially explosive gasoline without a second thought but the mere idea of getting near a flash capacitor freaks people out.

While both are dangerous in their own ways, it is good to have a little perspective.

 

[benjiboy]

while I certainly agree that it is important to respect these devices, fear for lack of understanding isn't going to do anybody any good.

Yes, a hit from one of those caps will make your eyes light up like a pinball machine. Trust me. I know. I've been bit by them a time or two. It doesn't tickle.
However, we should not treat them like ticking time bombs. If you understand what they do, how they work and how to handle them it is possible to experiment with them and be perfectly safe.

While I do not advocate that people take apart their flash guns and root around inside there with their fingers, I would certainly encourage somebody who has the will to learn and who has respect for what he's dealing with to investigate the inner workings of a flash that no longer works or is no longer needed. Just learn what the components are and how to identify them. Just about any good book on electronics that you can find in the library will teach you what you need to know.

This ain't black magic. Just be careful.

Unfortunately most people's knowledge and understanding are not matched by their actual ability s, and rather than read understand and inwardly digest the information therein the average person would rather fumble about blindly and get a shock that if there lucky isn't fatal.

 

[Worker 11811]

Yes, but don't you think that somebody who has the wherewithal to study and learn the technical aspects of photography and who can handle equipment and chemicals safely also has the presence of mind to study up on basic electronics before forging ahead and taking apart a camera flash?

I do agree, however, that a warning is in order. Those babies can and will bite if you don't watch out!

 

[Steve Smith]

I agree with Randy's comments.


Steve.

 

[benjiboy]

Yes, but don't you think that somebody who has the wherewithal to study and learn the technical aspects of photography and who can handle equipment and chemicals safely also has the presence of mind to study up on basic electronics before forging ahead and taking apart a camera flash?

I do agree, however, that a warning is in order. Those babies can and will bite if you don't watch out!

Apparently not many of them blithely tale their cameras apart which is fortunately not dangerous, but they only recount their successes, never their failures.

 

[ChuckP]

If enough people are dying from opening up flash cases maybe the manufacturers will put in an interlock system so if the case is opened a bleeder resister is automatically put across the capacitor.

 

[benjiboy]

If enough people are dying from opening up flash cases maybe the manufacturers will put in an interlock system so if the case is opened a bleeder resister is automatically put across the capacitor.

No I's natural selection, it ensures that the stupid are taken out of the gene pool.

 

[Athiril]

Cool! I've got a 2 in. dia. neodymium magnet. Grade N-45. I'll have to give that a try!

I dunno about one.. this is cause by gluing 10,000 gauss magnets together in a pattern, so they're all have opposing poles, cleaning up glue on a drum with acetone.. sometimes it'll dribble down where previously glued magnets are and the bonds will weak, when the magnet shifts slightly the forces crack it, and bits fly out at high speed.

 

[Monito]

[Had a question; figured out the answer]

 

[Worker 11811]

I used to have a dozen 1 inch spherical neodymium magnets. N-45's.

You learn, very quickly, to avoid leaving them lay loose on the table, especially if there are two or more within about two feet of each other. There's a darned good reason why they are shipped, individually packed, in plastic medicine bottles, separated by layers of bubble wrap and Styrofoam.

They are a lot of fun and they are pretty useful. You can learn a lot of interesting science. I use them for doing magic tricks for kids.

I USED TO have a dozen of them. Now, there are only two or three. Whole ones, anyway. Now I have a lot of broken pieces and a lot of bruised, pinched fingers.

 

[Leigh B]

This is no joke, even small electronic flashes are capable of delivering 10,000 Volts and a fatal shock.

No, they generate about 300 volts.

The circuitry is not capable of handling even 1,000 volts, much less 10,000.

- Leigh

 

[moki]

No, they generate about 300 volts.

The circuitry is not capable of handling even 1,000 volts, much less 10,000.

- Leigh

That's true. The one that shocked me was labeled 330V and others I've seen (without touching them myself) had a maximum of 350V. These things are far from deadly, unless you're very sensitive or have a serious medical condition. It still hurts like hell, so leave that stuff alone, if you don't know what you're doing... but that kind of panic is completely unnecessary.

By the way, saying something has 10.000V doesn't say much. It's not the voltage, that'll kill you, but the current. A few other factors are also important, but you should research those yourself, if you're interested.

 

[Leigh B]

Yes, any high-voltage shock will hurt, with intensity varying depending on the appendage involved.

Voltage is definitely a factor. The body has finite resistance that can be measured with any ohmmeter.

It varies quite a bit depending on perspiration and other factors, but 50,000 ohms is a good estimate.

Direct current of as little as 2 milliamps through the heart muscle will cause arrhythmia, which is fatal.
Applying 10,000 volts across a 50,000-ohm load will cause a current of 200 milliamps to flow.
The big unknown is the exact path that current will follow through the body, and in particular through the heart.

Studies have shown that current induced by voltages as low as 42 volts can be fatal.

As to the voltage rating on the capacitors...
The voltage rating is always higher than the actual voltage during operation, as a safety measure.
Good engineering practice requires a factor of 2 for most applications, i.e. a 400-volt rating for 200 volts applied.

- Leigh

 

[j-dogg]

I've repaired both my canon 540ez and 550ex multiple times. guess im lucky

 

[Monito]

I've repaired both my canon 540ez and 550ex multiple times. guess im lucky

Luck comes from good planning. Good planning includes education and practice.

 

[Leigh B]

I've repaired both my canon 540ez and 550ex multiple times. guess im lucky

Probably,

I was a warranty service station for Novatron studio strobes, and have a healthy respect for high-voltage circuitry.

In an earlier life, while I was going to night school, I worked for a company that serviced Sorensen commercial power supplies. When you work on one in that's rated 10 AMPS at 5,000 volts, carried in on a fork lift, you're reluctant to take chances.

- Leigh

 

[Discoman]

Something to note is that some of the older caps can still retain a hefty charge even after being 'drained'. After a few minutes, or hours, the residual charge can appear at the terminals, making for nasty surprises.

My advice as an extension to this: many caps that carry higher voltages can store their power for easily several weeks after being unplugged. High voltage caps can still pack a very nasty surprise a month later.
Unplug the device for a couple weeks, the use a resistor discharge.
I have a book somewhere that has some HV projects and it has how to properly discharge caps, and how to do so safely.

 

[albada]

As to the voltage rating on the capacitors...
The voltage rating is always higher than the actual voltage during operation, as a safety measure.
Good engineering practice requires a factor of 2 for most applications, i.e. a 400-volt rating for 200 volts applied.
- Leigh

I've done a number of repairs and modifications of flash units. Yes, those caps are dangerous! I always put a large bleeder resistor across them before doing anything to a flash unit.

Anyway, that 2x safety factor is *not* followed inside most flash units. If the cap is rated at 330V, then that's probably what the flash will charge it to with fresh batteries.

Mark Overton

 

[Leigh B]

I've done a number of repairs and modifications of flash units. Yes, those caps are dangerous! I always put a large bleeder resistor across them before doing anything to a flash unit.

Having serviced many studio flash systems, and I concur in the use of a bleeder resistor in all cases. Better bled than dead. (Sorry )

Anyway, that 2x safety factor is *not* followed inside most flash units. If the cap is rated at 330V, then that's probably what the flash will charge it to with fresh batteries.

The operating environment of a battery-powered flash is very different from that found in an AC-powered flash.
Battery-powered units are generally incapable of generating over-voltage conditions, while that problem is quite common in AC-powered units.

The other constraint on electrolytic capacitors is the products available on the market. Caps rated higher than 500 volts are quite uncommon, so it's difficult to meet the 2x goal, but it's quite common to find caps rated at voltages significantly higher than nominal operating voltage.

- Leigh

 

[JBrunner]

It's really very simple. All electronics run on magic smoke that the scientist guys put in them. I have verified this by repeated observation. Whenever the magic smoke gets out of one of my gadgets, it doesn't work anymore.