Do you pop your flashes at least once per month?

Theo Sulphate · Aug 29, 2016

Reading my newly acquired SB-20 manual, it states that if the flash unit isn't going to be used for a long period of time, then it should be fired a few times at least once per month to "reform the capacitor".

I've since seen this in other manuals and have found postings on the net where a perfectly new flash has died after six months of non-use. This was a relatively new SB-800.

Wouldn't this apply to new flash units stored away at Amazon, B&H, etc.?

What is your experience with this? Although my flash units are inexpensive, I'd like to keep them working.

Poisson Du Jour · Aug 29, 2016

Doesn't seem sensible to me for retailers to store flashes for an extended period with batteries loaded, until such time eventuates as there is a demonstration. My only flash is a Canon 540EZ bought in 1994 with my EOS 1N. I last used this flash during star trails foreground illumination in January this year (probably not used for a year or two years before then), and again on 24th July (lithium batteries are in use). Over a long period of time I think there is a greater risk of battery leakage rather than something going akimbo with a capacitor / thyristor or whatnot. That is the warning in the 540EZ manual (to remove batteries if the flash is not in use for a long period of time).

AgX · Aug 29, 2016

Theo Sulphate said:
I've since seen this in other manuals and have found postings on the net where a perfectly new flash has died after six months of non-use. This was a relatively new SB-800.

No new flash dies from not using.

But masx. capacity can decrease over storing time. Charging can "refresh" a capacitator. That is what the advise in some manuals is about.
However advice how to do so vary much.

On the other hand, over long time (decades) capacitators can deteriorate. Some forms of decay might be prevented by refreshing other seem to be inherent to the design of the capacitator.

Nevertheless, within my collection, a faulty flash belongs to the rarer cases.
(Except for built in NiCad batteries.)

RalphLambrecht · Aug 29, 2016

Theo Sulphate said:
Reading my newly acquired SB-20 manual, it states that if the flash unit isn't going to be used for a long period of time, then it should be fired a few times at least once per month to "reform the capacitor".

I've since seen this in other manuals and have found postings on the net where a perfectly new flash has died after six months of non-use. This was a relatively new SB-800.

Wouldn't this apply to new flash units stored away at Amazon, B&H, etc.?

What is your experience with this? Although my flash units are inexpensive, I'd like to keep them working.

one can spend 8h/day on photoaquipment maintenance,but,yes,I fire mine regular to keep them working and also fire the shutters of all mechanical cameras at all speeds to keep them working too. things need to work to keep working.

DWThomas · Aug 29, 2016

There may be merit in the idea, but I don't do it. My latest greatest one gets used at least once or twice a year and seems fine. I do not leave batteries installed in any of my flashes. The Canon 188A I use(d) with my A-1 still worked the last time I tried it, but a couple of older units (back to the 1970s or about) won't start, which is a typical sign of the capacitor being shot. No idea if revving it up periodically would have helped, but they are ancient. And yes "forming" is the expression, in effect revitalizing the microscopic oxide layer that is the dielectric to reduce electrical leakage.

M Carter · Aug 29, 2016

I came across my old Vivitar 285 a few months ago - which must have sat in a box for a decade - and it works fine.

I try to remember to do this to my Speedo packs every month or two if they haven't been used, but I have 5 or 6 of 'em so, in reality... they get formed when they go out on a gig.

I have an 802 that hasn't been powered up in probably 2-3 years, maybe I'll give it a try and see how it's holding up.

wiltw · Aug 29, 2016

Frequency of 'reforming the capacitor' varies from brand to brand...

I have a user manual from a Honeywell unit in the mid-1960s which mentions 'if you have not used the flash in a few days' to turn on for 15 minutes,
my Dynalite says once a month to turn on 'for a few hours',
my Metz instruction says 'every 3 months' to simply TURN ON and leave on the pack (no need to flash).

Eric Rose · Aug 29, 2016

skorpiius · Aug 29, 2016

I don't do this, but I might start now

StephenT · Aug 29, 2016

I don't - I have way too many flashes and would have to make a career out of maintenance flashing. From a technical standpoint, it would indeed be beneficial. However, from my experience over 50 years or so, I have never had a flash fail from non-use. Prior to actually using a flash, I will let it charge up, fire it at full power a few times so as to "re-form" the capacitor, and go from there. If you only have one or two, it would not be a bad idea to put it as a recurring appointment on your smart phone and have fun.

Sirius Glass · Aug 29, 2016

Eric Rose said:
no

That is what I said.

benjiboy · Aug 29, 2016

No I just remove the batteries from them after I have used them.

AgX · Sep 13, 2016

When using an old, long stored flash you may experience that ready-indicator does not light up. But nevertheless the auto-exposure function works and the manual setting will give a higher output.
In this case the capacitator may leake electrically and not reach nominal charge.
Forming of that flash may restore the full-charge and and indicator function.

AgX · Sep 13, 2016

If during forming you
-) hear a sizzling noise (which is not that transforming hiss)
or
-) feel the flash getting hot,

stop charging and discard the flash (or repair it, most likely substituting main capacitator).

TSSPro · Nov 9, 2016

Had several Dynalight packs that had been in storage for an extended period of time experience issues with the capacitors before. The packs were serviced by Dynalight, briefly used for a year and then put into storage for more than a year. When they came out of storage the capacitors wouldn't even hold enough charge to fire the tubes. I worked with each of the packs that were experiencing this issue for several days and I was only able to train or re-gain marginal capacity in the capacitors. It was a lot of sitting on the living room floor with each of the packs plugged in with a head just firing and recharging the capacitors. After several hours and several days seeing significant improvement in the flash output......I gave up. I honestly regret quitting my attempts to bring back those packs, but it seemed like it was too daunting of a task and I needed strobes before those would be back to their normal performance.

Leigh B · Nov 9, 2016

Degradation happens quite predictably when electrolytic capacitors are stored without any voltage applied for a long period of time.

It's a consequence of leakage developing within the insulation layer (the electrolyte).
It's a very well-known phenomenon, with a 100-year history.

Voltage is applied across a capacitor when the equipment is first turns on, and usually remains present as long as it's on.
Sometimes it varies, as when a flash fires, but it rebuilds to maximum in a few seconds.

The electrolyte is an insulator, but not a perfect insulator. Think of it as a layer of bubbles that form when voltage is present.
When no voltage is present, the bubbles slowly dissipate. That progresses over time until they're all gone, resulting in a short circuit.

If you apply full voltage across a degraded capacitor it will likely explode.

The electrolyte is a paste having a small percentage of water.
Current flowing through leakage resistance creates heat. That heat creates steam.
Steam pressure builds to the point of rupturing the package. Larger caps have safety vents to release it.

The only way to "revive" a degraded capacitor to the point that it will work properly is to "re-form" it.
VERY IMPORTANT: Before starting this, ensure that a fuse of the correct type and value is installed in the equipment.

As i mentioned, the insulating bubble layer is formed when voltage is applied.
To avoid an explosion, this must be done for a very short period of time initially.

If at any time a failure is noted or the fuse blows... Turn it OFF, unplug it, and refer it to a proper service shop.

Pick a time of day (noon or whenever) to start each stage. DO NOT fire the flash (if it is a flash).
On day 1: turn the equipment on for ONE minute, then off and leave it alone til the next day.
On day 2: turn the equipment on for TWO minutes, then off and leave it til the next day.
ON day 3: turn the equipment on for FOUR minutes, then off...
Repeat on subsequent days, doubling the ON time each day, i.e. 8... 16...32...64 minutes.

At the end of a week the gear should work OK for over an hour. It should then be "re-formed" if it can be.

- Leigh

AgX · Nov 9, 2016

There are various recipes for regenerating electrolytic capacitators, but your time regime makes no sense to me. Only the time with applied voltage will be effective.
The seemingly best ways for regenerating or testing, as these yield full control on the process and its variables, will need to desolder the flash, something with means hassle with compact flashes.

Sirius Glass · Nov 9, 2016

If you have owned a strobe for all those years without using it, you can probably afford to go out and buy the latest model. Then put the new strobe back on the same shelf and let it sit for years too.

Leigh B · Nov 9, 2016

{Please note the following discussion applies to "aluminum electrolytics" of the kind that have been in use since the 1930s.
These are the type we're likely to encounter in vintage equipment.
It does not apply to the latest generation of electrolytics, but that's not what we're discussing.}

AgX said:
There are various recipes for regenerating electrolytic capacitators, but your time regime makes no sense to me.

Then permit me to educate you.

Electrolytics are packaged in sealed metal cans.

Failures are the result of internal pressure rising to the point the cap explodes.

The un-powered interval provides time for that pressure to dissipate close to normal atmospheric, so no explosion.

AgX said:
Only the time with applied voltage will be effective.

The power-on interval serves to rebuild the electrolytic insulating layer.
That happens whenever voltage is applied to the cap.

So we have two related but competing processes...
1 - Current must flow through the electrolyte to build the bubble layer.
2 - But that current generates heat, steam, and pressure, which we don't want.

The progressive-interval method I recommend keeps the pressure down while expediting the repair.

AgX said:
The seemingly best ways for regenerating or testing, as these yield full control on the process and its variables, will need to desolder the flash, something with means hassle with compact flashes.

The technique I recommend has been used successfully by me and other service techs for at least 60 years.
I've been repairing high-voltage electronics since c. 1955.

I recommend it because no special equipment or dis-assembly of the product is required.
It can be done by anyone using no tools.

Flash systems are high-voltage circuits by their very nature. Those voltages can be lethal.

I was a warranty service center for Novatron studio strobes.
I had to sign a statement that if I killed myself, it was not their fault.

These things CAN kill you.
There's no way I would suggest any untrained individual open one up and mess around inside.

- Leigh

benjiboy · Nov 9, 2016

Leigh B said:
Degradation happens quite predictably when electrolytic capacitors are stored without any voltage applied for a long period of time.

It's a consequence of leakage developing within the insulation layer (the electrolyte).
It's a very well-known phenomenon, with a 100-year history.

Voltage is applied across a capacitor when the equipment is first turns on, and usually remains present as long as it's on.
Sometimes it varies, as when a flash fires, but it rebuilds to maximum in a few seconds.

The electrolyte is an insulator, but not a perfect insulator. Think of it as a layer of bubbles that form when voltage is present.
When no voltage is present, the bubbles slowly dissipate. That progresses over time until they're all gone, resulting in a short circuit.

If you apply full voltage across a degraded capacitor it will likely explode.

The electrolyte is a paste having a small percentage of water.
Current flowing through leakage resistance creates heat. That heat creates steam.
Steam pressure builds to the point of rupturing the package. Larger caps have safety vents to release it.

The only way to "revive" a degraded capacitor to the point that it will work properly is to "re-form" it.
VERY IMPORTANT: Before starting this, ensure that a fuse of the correct type and value is installed in the equipment.

As i mentioned, the insulating bubble layer is formed when voltage is applied.
To avoid an explosion, this must be done for a very short period of time initially.

If at any time a failure is noted or the fuse blows... Turn it OFF, unplug it, and refer it to a proper service shop.

Pick a time of day (noon or whenever) to start each stage. DO NOT fire the flash (if it is a flash).
On day 1: turn the equipment on for ONE minute, then off and leave it alone til the next day.
On day 2: turn the equipment on for TWO minutes, then off and leave it til the next day.
ON day 3: turn the equipment on for FOUR minutes, then off...
Repeat on subsequent days, doubling the ON time each day, i.e. 8... 16...32...64 minutes.

At the end of a week the gear should work OK for over an hour. It should then be "re-formed" if it can be.

- Leigh

Life's too short

Ozxplorer · Nov 10, 2016

benjiboy said:
Life's too short

As usual there is in every group a "salmon" prepared to go against the flow... Expert opinion counts for little until one day the "smart alec" realises that failure to take heed will cost! At least once every 2 months I power up my flashes both for camera and floor standing studio lighting in order to condition the capacitors. Have done so since the late 60's... Some may not do this but this works for me... it is called "taking care of business" or, as the saying goes: "use it or lose it"... Fred

AgX · Nov 10, 2016

Leigh,
I got your point on the time regime related to built-up gasses. I did not think of that. Thank you.
The idea of regenerating capacitators in the disconnected state is that you have full control on the leak-current, by that (likely) avoiding pressure-built-up.
Problem is that the recipes I know differ on that maximum current by magnitudes...

Ozexplorer,
problem is that we not only got flashes that are regularly formed after acquiring from the manufacturer as likely in your case, but also cases where one buys flashes with unknown history, maybe uncharged for decades.
I know of people who in such cases do not even switch on such device without not having taken out each and every electrolytic capacitor and testing and regenerating them.
So far I did not follow that way, but I got a flash capacitator starting to boil within minutes after just switching that flash on.

wombat2go · Nov 10, 2016

I recently tested (6) old electro capacitors that I had removed and replaced in a
HP6253A power supply vintage about 1967.
One electro had failed in this unit so I had replaced them all.
They were Sprague 490 uH 85 Vdc .
The unfailed ones, about 49 years old, showed no visual signs of leakage of electrolyte.

Firstly I charged them to 25 V dc and measured the capacitance by discharge time
to 37% through a 12 K resistor. All were slightly higher than 490 uF

Then I measured the leakage as they sat with 25 Vdc steady voltage.
Typically the leakage dropped from an initial 76 microAmp to settle at 17 microAmp.

The leakage specification for present day Nichicon is I_Leak= 3*sqrt(C*V) ( at max rated temperature and voltage)
so by that, these capacitors would have an allowable leakage of 612 microAmp

Finally I measured the small signal impedance at 10 kHz
490 uF has an ideal reactance of (-j) 0.032 Ohm
The | impedance | was 0.114 Ohm
The impedance is a combination of series inductance and equivalent series resistance (ESR).
These are just filter caps and I had no data on ESR for them.

However ESR ( an important spec for photo flash duty) does increase with age, and as ambient temperature reduces.
A long time ago I tested some pulse duty electro caps for military use in a cold chamber.
The ESR does increase when cold rendering the capacitor less able to provide fast rising high current pulses.
( I forget but the circuit I was testing became inop at cold start from about minus 20 celsius. )

General electro caps have reduced in physical size over past 50 years, so it is easy to replace them.

However recently I was helping a member on another forum to find a replacement electrolytic for an old flash from about 1980's
I noticed the specific flash duty capacitors are available as replacements parts,
but are not physically smaller than the original ones from old times.
In that case we could not find a replacement of the same diameter and length.

Leigh B · Nov 10, 2016

AgX said:
I got your point on the time regime related to built-up gasses. I did not think of that. Thank you.
The idea of regenerating capacitators in the disconnected state is that you have full control on the leak-current, by that (likely) avoiding pressure-built-up.

The process i described was optimized for safety, not efficiency.

It can be done by anyone who has zero technical training and capability without endangering himself or the equipment.
I even use it for routine maintenance because I'm lazy and the process is easy.

For bench work, of course I re-form caps which are disconnected from the circuit.
That gives me more control over the process.

i even designed a 1 milliamp constant-current power supply that re-forms caps using advanced control circuitry.
Here's a PDF of the design (WARNING... this produces 1000 volts open-circuit):
http://www.atwaterkent.info/Images/CapFormerSchematic.pdf
It's a simple matter to modify the design to limit the max voltage to 500 volts.

- Leigh

RalphLambrecht · Nov 10, 2016

Theo Sulphate said:
Reading my newly acquired SB-20 manual, it states that if the flash unit isn't going to be used for a long period of time, then it should be fired a few times at least once per month to "reform the capacitor".

I've since seen this in other manuals and have found postings on the net where a perfectly new flash has died after six months of non-use. This was a relatively new SB-800.

Wouldn't this apply to new flash units stored away at Amazon, B&H, etc.?

What is your experience with this? Although my flash units are inexpensive, I'd like to keep them working.

my flashes are used on a regular basis's,Yes ,that keeps them going

Do you pop your flashes at least once per month?

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