METZ 45 Flashgun Capacitors
The puropose of this is to tell you what capacitor you need for a METZ 45 flashgun.
The other day I got a non-working METZ 45CL-5 flashgun. I bought it for the bits. When I tried to charge it up it made a clicking noise (the reason why it was sold as not working).
The noise was a repeated electric breakdown in the main electrolytic capacitor. As the voltage in the capacitor rose (as it charged) it reached a value that causes a flash-over between the two layers in the capacititor. The capacitor can also got hot at that place.
The options were:
a) Fit a new capacitor.
b) Swap a capacitor from and older METZ that was not used much.
c) Scrap it
It seemed a shame to scrap it, The 45CL-4 is a nice gun.
The first problem was the rating of the capacitor. It only had a Siemens reference number on it.
Lots of web forums gave the rating as 1500uF 250V.. I was suspicious of the 250V, but kept finding people who said it was this value.
Eventually I got to the truth - the actual rating is 400uF 360V DC
Lesson 1: Don't trust what people tell you, no matter how many of them repeat the stuff.
I could buy a suitable capcitor (40mm x 60mm) but the cost was more than shopping around for a used replacement flashgun.
I did have an old, tatty METZ CT-1 The CL-5 is much better, so I swapped the capacitor over.
Lesson 2: If you dismantle a flashgun, the capacitor will have a residual charge. It would be difficult for it to kill you (the current has to pass across your heart). Touching either terminal on its own won't hurt because there is no return path, but you don't want to make contact with both terminals. I have never done it, but I am told it hurts a lot. Just put a high value resistor (about 1M) across the terminals and let the capacitior discharge before trying to unsolder it.
Now I have a fully working 45CL-5.
The other day I got a non-working METZ 45CL-5 flashgun. I bought it for the bits. When I tried to charge it up it made a clicking noise (the reason why it was sold as not working).
The noise was a repeated electric breakdown in the main electrolytic capacitor. As the voltage in the capacitor rose (as it charged) it reached a value that causes a flash-over between the two layers in the capacititor. The capacitor can also got hot at that place.
The options were:
a) Fit a new capacitor.
b) Swap a capacitor from and older METZ that was not used much.
c) Scrap it
It seemed a shame to scrap it, The 45CL-4 is a nice gun.
The first problem was the rating of the capacitor. It only had a Siemens reference number on it.
Lots of web forums gave the rating as 1500uF 250V.. I was suspicious of the 250V, but kept finding people who said it was this value.
Eventually I got to the truth - the actual rating is 400uF 360V DC
Lesson 1: Don't trust what people tell you, no matter how many of them repeat the stuff.
I could buy a suitable capcitor (40mm x 60mm) but the cost was more than shopping around for a used replacement flashgun.
I did have an old, tatty METZ CT-1 The CL-5 is much better, so I swapped the capacitor over.
Lesson 2: If you dismantle a flashgun, the capacitor will have a residual charge. It would be difficult for it to kill you (the current has to pass across your heart). Touching either terminal on its own won't hurt because there is no return path, but you don't want to make contact with both terminals. I have never done it, but I am told it hurts a lot. Just put a high value resistor (about 1M) across the terminals and let the capacitior discharge before trying to unsolder it.
Now I have a fully working 45CL-5.
The usual advice is that only trained people should ever work on flash equipment. The stored energy is potentially lethal.
Portable flash equipment like the Metz will generally use 360 volts so you need to make sure your main capacitor is rated at 360V WORKING. Studio flash units frequently use 408V and the capacitor bank often stores up to 6400J. This is enough energy to kill several people!
Flash capacitors must have a discharge resistor connected across the main terminals so that the stored charge can leak away after the unit is de-powered. Failure to fit the discharge resistor could prove lethal to the next person to work on the unit. Please check.
There are only a couple of factories in the world that produce flash capacitors and they're a specialist product because they're designed to discharge so quickly. An ordinary capacitor of similar rating won't do.
Portable flash equipment like the Metz will generally use 360 volts so you need to make sure your main capacitor is rated at 360V WORKING. Studio flash units frequently use 408V and the capacitor bank often stores up to 6400J. This is enough energy to kill several people!
Flash capacitors must have a discharge resistor connected across the main terminals so that the stored charge can leak away after the unit is de-powered. Failure to fit the discharge resistor could prove lethal to the next person to work on the unit. Please check.
There are only a couple of factories in the world that produce flash capacitors and they're a specialist product because they're designed to discharge so quickly. An ordinary capacitor of similar rating won't do.
This morning my beloved 45 CL went bang in my hand. It is a backup or used when I want two flashes. It had smoke coming from the battery compartment so it was obvious the capacitor had blown. Well I did buy it in 1991!
I used to be an electronic engineer, so I decided to take it apart and after checking many data sheets and forum posts, decided this was a 400uF 360V Pulse capacitor. The original is obsolete so I had to find an equivalent, this is it (I hope):
Vishay Extreme 390μF 500 V Aluminium Electrolytic Capacitor, 159 PUL-SI
This is a pulse capacitor that is rated at 500V instead of 360V, so should be more durable. The 10uF less in capacitance is negligible and will probably be made made up for in the 25 year technology gap, tolerances and all that.
Although it states low efr, 350M Ohm doesn't seem that low compared to others, we will see.
Anyhoo, I have ordered it, free postage next day delivery, I will get it Monday and fit it then.
I will let you know if it goes bang or fails to work at all
BTW, I see lots of stuff about how dangerous capacitors are and they can kill you. That may be so, but highly unlikely, especially from a 360V 400uF capacitor. As mine was already dead and I could do no further damage, I just held a pair of tweezers in a cloth and shorted out the terminals, there was a small spark. You could use a 500k resistor if you wish. Don't be afraid
I used to be an electronic engineer, so I decided to take it apart and after checking many data sheets and forum posts, decided this was a 400uF 360V Pulse capacitor. The original is obsolete so I had to find an equivalent, this is it (I hope):
Vishay Extreme 390μF 500 V Aluminium Electrolytic Capacitor, 159 PUL-SI
This is a pulse capacitor that is rated at 500V instead of 360V, so should be more durable. The 10uF less in capacitance is negligible and will probably be made made up for in the 25 year technology gap, tolerances and all that.
Although it states low efr, 350M Ohm doesn't seem that low compared to others, we will see.
Anyhoo, I have ordered it, free postage next day delivery, I will get it Monday and fit it then.
I will let you know if it goes bang or fails to work at all
BTW, I see lots of stuff about how dangerous capacitors are and they can kill you. That may be so, but highly unlikely, especially from a 360V 400uF capacitor. As mine was already dead and I could do no further damage, I just held a pair of tweezers in a cloth and shorted out the terminals, there was a small spark. You could use a 500k resistor if you wish. Don't be afraid
There's a good reason why high-voltage capacitors can be lethal: they're designed to give out a large amount of energy, hundreds or thousands of Joules, and in a very short time, typically tens or hundreds of microseconds. Not really for the hobbyist!
I was trained as an electrical engineer.
I was trained as an electrical engineer.
Well that's interesting, but a 400uF capacitor charged to 240V (2/3 of it max voltage) will store about 120 Joules of energy. A boiled egg, by the way, has about 600,000 Joules of energy, although I am not suggesting this will kill you, unless you try and eat it whole and choke.
Also high voltage, in my day was anything over 800V, now I believe it's over 600V.
Shocks from these electronic capacitors are like static shocks, and as they are DC, and going through at least 100,000 Ohms of body resistance (impedance), will produce less than 2mA across the heart for a microsecond, if you shorted it with the left and right hand.
I think they could cause you to die if you fell off your chair and hit your head from the reaction of pulling your hand away
Also high voltage, in my day was anything over 800V, now I believe it's over 600V.
Shocks from these electronic capacitors are like static shocks, and as they are DC, and going through at least 100,000 Ohms of body resistance (impedance), will produce less than 2mA across the heart for a microsecond, if you shorted it with the left and right hand.
I think they could cause you to die if you fell off your chair and hit your head from the reaction of pulling your hand away
Quote:Well that's interesting, but a 400uF capacitor charged to 240V (2/3 of it max voltage) will store about 120 Joules of energy.
In my day we could correctly calculate the energy stored in a capacitor. Try again. By the way, the forum works perfectly well without Activex.
Quote:Well that's interesting, but a 400uF capacitor charged to 240V (2/3 of it max voltage) will store about 120 Joules of energy. A boiled egg, by the way, has about 600,000 Joules of energy, although I am not suggesting this will kill you, unless you try and eat it whole and choke.
Also high voltage, in my day was anything over 800V, now I believe it's over 600V.
Shocks from these electronic capacitors are like static shocks, and as they are DC, and going through at least 100,000 Ohms of body resistance (impedance), will produce less than 2mA across the heart for a microsecond, if you shorted it with the left and right hand.
I think they could cause you to die if you fell off your chair and hit your head from the reaction of pulling your hand away
Let's hope they don't put you in charge of Elfin Safety!
I'll concede the point about "high voltage" not being correct in the legal sense. Believe me, the capacitors in studio flash packs are lethal, typically 3200J at 480 Volts
Hehe, that's what you get when you're senile and do a rough calculation in your head! Wrong by an order of 10, but hey ho, it holds even less, only about 12 Joules.
Big studio flash are only 500 Ws or 500 Joules. The capacitors usually give this energy out in 1000th of a second. I have my doubts that would harm you either.
Assuming the voltage is 480V and the Capacitor is 5000uF holding 576 Joules, it would give you less than 5mA from left to right hand. Not a pleasant feeling, but I doubt it would be life threatening. Shocks that kill would usually be sustained currents of over 100mA, not a fraction of a second burst from a capacitor.of this size.
Anyway, as I said, it's easy to discharge a capacitor fully before touching it, so no probs.....
Big studio flash are only 500 Ws or 500 Joules. The capacitors usually give this energy out in 1000th of a second. I have my doubts that would harm you either.
Assuming the voltage is 480V and the Capacitor is 5000uF holding 576 Joules, it would give you less than 5mA from left to right hand. Not a pleasant feeling, but I doubt it would be life threatening. Shocks that kill would usually be sustained currents of over 100mA, not a fraction of a second burst from a capacitor.of this size.
Anyway, as I said, it's easy to discharge a capacitor fully before touching it, so no probs.....
With the greatest of respect, the Broncolor packs that we use come in 3 sizes, 1600J, 3200J and 6400J but we've never had the largest. Most monoblocks are lower power.
I wouldn't advise my worst enemy to try a hand-hand discharge.
Flash and other high-power capacitors should have a discharge resistor fitted across the terminals. Some years back I had a shock from a baby-size 375J pack after it had been turned off for a few minutes and that hurt!
I wouldn't advise my worst enemy to try a hand-hand discharge.
Flash and other high-power capacitors should have a discharge resistor fitted across the terminals. Some years back I had a shock from a baby-size 375J pack after it had been turned off for a few minutes and that hurt!
With even greater respect, I have seen so many fear posts regarding flash repair and capacitors that it makes me wonder if the repairers are posting these scare stories.
I am posting about battery camera flash capacitor replacement and you start talking about a Bronocolor Scoro at over £5,000. I think it highly unlikely that a photographer owning one of those will be taking it apart
There is no danger from capacitors in standard battery camera flashes, unless, as I stated previously, you fall off the chair and hit your head.
I started by repairing TVs, got a Masters in electronics, worked at GEC Avionics and never even spoke about capacitors as we had all had a minor shock from one. Warning people as if they are going to be seriously hurt by a capacitor that is charged by a 9V battery pack is inappropriate and misleading. A scare story to discourage people repairing their own flashguns and encouraging them to pay through the nose to have a £10 replacement fitted.
If you do a Google search on this topic you will see many of these scare posts, where someone wants to repair their equipment, there is someone else trying to scare them into not touching it. I agree if it a mains appliance, an amateur can do damage to the equipment and potentially themselves, but this thread is about portable battery flash!
I am posting about battery camera flash capacitor replacement and you start talking about a Bronocolor Scoro at over £5,000. I think it highly unlikely that a photographer owning one of those will be taking it apart
There is no danger from capacitors in standard battery camera flashes, unless, as I stated previously, you fall off the chair and hit your head.
I started by repairing TVs, got a Masters in electronics, worked at GEC Avionics and never even spoke about capacitors as we had all had a minor shock from one. Warning people as if they are going to be seriously hurt by a capacitor that is charged by a 9V battery pack is inappropriate and misleading. A scare story to discourage people repairing their own flashguns and encouraging them to pay through the nose to have a £10 replacement fitted.
If you do a Google search on this topic you will see many of these scare posts, where someone wants to repair their equipment, there is someone else trying to scare them into not touching it. I agree if it a mains appliance, an amateur can do damage to the equipment and potentially themselves, but this thread is about portable battery flash!
I've repaired plenty of flash units over the last 40 years, both portable and studio and I thoroughly understand the dangers, so that's why I give the warning. Electric shocks are most dangerous to the very young, the elderly and the infirm and our procedures and precautions need to be geared towards the most vulnerable. Modern flash capacitors have a lower ESR than used to be the case and so can discharge much faster. Portable flash is also more powerful than it used to be.
Whether or not people heed the warning isn't my responsibility.
I'd also try to dissuade people from doing their own domestic wiring if they haven't had the appropriate training.
Whether or not people heed the warning isn't my responsibility.
I'd also try to dissuade people from doing their own domestic wiring if they haven't had the appropriate training.
, I was able to complete the repair as a zombie. In the video I was shorting the capacitor to the case sometimes, which is why you hear the crack but no flash.
These days, Metz 45 series flash units are so cheap on Fleabay that it surely can't be worth fixing!
Technical Note.
Energy calculation for charged capacitor:
1/2(CV.V) joules
Taking values: V = 240V, C = 400uF = 400/1000000F = 0.0004F
1/2(0.0004 x 240x240) = 11.52 joules
However, the danger to the human body is the amount of current that is passed through it after the initial skin resistance is broken down. Especially if it passes through the heart.
240v is 240v after all!
Also j = v.i.t joules = volt x current x seconds
Hence i = j / (v.t) amperes
So there is a time consideration of the current passing through the body as the capacitor discharges.
(Hence the fast trip speed of electrical safety devices (cut-outs) generally used).
Energy calculation for charged capacitor:
1/2(CV.V) joules
Taking values: V = 240V, C = 400uF = 400/1000000F = 0.0004F
1/2(0.0004 x 240x240) = 11.52 joules
However, the danger to the human body is the amount of current that is passed through it after the initial skin resistance is broken down. Especially if it passes through the heart.
240v is 240v after all!
Also j = v.i.t joules = volt x current x seconds
Hence i = j / (v.t) amperes
So there is a time consideration of the current passing through the body as the capacitor discharges.
(Hence the fast trip speed of electrical safety devices (cut-outs) generally used).
