Strobe Capacitors

I have two 1990’s vintage strobes. A Vivitar 285HV & a Metz 45 TC-3.
Both have been “dead” for some time in a box with no batteries. All battery contacts have been cleaned.

I have tried "Reforming the capacitors." With not much luck using new batteries & a.c. The 285HV did fire 5-6 times & died, it never came back after a couple days of trying. The Metz never showed any signs of life……

Question:
Has anyone seen a “cross reference chart” for today’s capacitors for these old units before opened up? (I know not to open them and stick my fingers, toes or tongue in before it is discharged). I have a electronics friend that will install new ones if I can find them.

Thought it might be worth a try before I throw the box out.
Thanks for any help…

the values of the caps will be printed on them. new ones can be had at mouser or digikey.

There used to be special capacitors identified as "photoflash" capacitors. Those haven't been made in decades.

The relevant modern characteristic is ESR (equivalent series resistance).
Given a choice among several otherwise identical caps, get the one with the smallest ESR value (expressed in ohms).

Electrolytic caps have two major characteristics: voltage (in volts) and capacitance (in microfarads or mfd).
When replacing an old one, get a capacitance value equal to or a bit higher, as close as possible.
The DC voltage rating of the new part MUST equal or exceed the rating of the original... no exceptions.

You should match the case style of the original. Cylinders with one lead sticking out each end are called "axials".
Cylinders or lozenge shapes with two parallel leads sticking out one side are called "radials".

Make sure your new connections match the polarity of the old caps, positive (+) and negative (-).
Older (US-made) caps identified the positive lead with a plus sign (+), no marking on the negative lead.
Modern caps identify the negative lead with a minus sign (-), no marking on the positive lead.
This can cause confusion because the minus sign is not always obvious.

Good sources for older values are Mouser, Allied, and Newark.
Dead Link Removed
www.alliedelec.com
www.newark.com

- Leigh

Leigh B said:

There used to be special capacitors identified as "photoflash" capacitors. Those haven't been made in decades.

Click to expand...

Photoflash capacitators are still in the range of some capacitator manufacturers.

AgX said:

Photoflash capacitators are still in the range of some capacitator manufacturers.

Click to expand...

I don't understand what "range" means in this context.
Do you mean they still have capacitors with that description in their product line?

On edit:
Well, I stand corrected.

Mouser does have 23 different "photo" electrolytics, from two different companies.
But only one of those 23 products is actually stocked, a 330mfd @ 300V can style.
It's far too large to fit in a camera flash; more for a studio strobe power pack.

- Leigh

Leigh, I recall you worked in this field professionally, yes? Do you have some ESR specs to recommend that would be similar to "photoflash" specs?
uOhms? mOhms? single digit Ohms?

ic-racer said:

Leigh, I recall you worked in this field professionally, yes?
Do you have some ESR specs to recommend that would be similar to "photoflash" specs?
uOhms? mOhms? single digit Ohms?

Click to expand...

Hi,

Yes, I've done electronic repair professionally since high school (over 60 years ago).
I was a warranty service station for Novatron studio strobes for a few years.

I have no specific ESR numbers, since that varies with technology and each cap's voltage and mfd.
Some representative numbers of good-quality parts:
300mfd @ 330VDC ESR = 663 mOhms
500mfd @ 330VDC ESR = 398 mOhms
1200mfd @ 360VDC ESR = 166 mOhms
As you can see, ESR decreases with capacitance due to the larger surface area involved.

I mentioned it to suggest comparing multiple otherwise identical caps... take the one with the lowest ESR.
The selection is definitely not critical, and will not significantly affect operation of the unit.
I take lower ESR to be an indication of higher quality (personal opinion).

ESR can be important in specific situations, like a real stroboscope that flashes continuously.
Caps in that situation will heat. Those with higher ESR will get hotter.

- Leigh

Thanks for your replies.
I did get some information on one of the units.
It's worth looking at the video....

Vivitar 285HV:
I have been in contact with the author of this informational video.

As I have been told by anothers.
“You may have trouble finding a capacitor that fits your unit”.

This was his reply to me:

“The large capacitor in the Vivitar strobe is around 1000 uF at 330 volts dc. As I recall the originals were 1100 uF, but I could not find any of that value and correct physical size. The 1000 uF seem to work without any issues. I found a Rubycon (a top of the line brand) on eBay (see below).

Make sure that the replacement capacitors are rated for photo strobes. The capacitor should say “PHOTO” or for use in strobes, or something of that nature. The Rubycon capacitor has “PHOTO” on them. This is important since strobes discharge and charges constantly when taking photos and the capacitors will heat up. Regular capacitors will fail because they are not made for that type of cycling and heat. Also, make sure the new capacitor will fit in the strobe. The Rubycon I used measure approximately 50mm high (includes terminals) and 30mm in diameter.

Do an eBay search for PHOTO Flash capacitor 1000uF 360v Pulse strobe Low ESR photoflash foto 330v, those are the ones I purchased and they seem to work just fine. I know it says 360v, but the caps are really 330v. They are just a little smaller than the originals, but you can put some double-backed tape on it and it will fit perfectly. I notice that the size given for diameter is now 35mm, so they may fit better. There cost is $17.17 plus shipping. A lot cheaper than purchasing a new strobe. They also carry strobe tubes.

Remember THERE ARE HIGH VOLTAGES INSIDE THE STROBE, even if the capacitor is old or discharged, so MAKE SURE ALL HIGH VOLTAGE IS DISCHARGED as I showed in the video before touching the wires to the capacitor, circuit board or strobe tube, even if THE BATTERIES ARE REMOVED”.
Good luck in fixing your strobe,
Charles Legg

kmphoto said:

This was his reply to me:

Click to expand...

All good info.

It appears he's been at this for a while.

There's a very odd phenomenon that I hope you will not encounter.

Under some circumstances, electrolytic caps will re-charge themselves.

The common situation is removing a cap from the equipment and let it sit on the bench, disconnected.
Some caps will have the charge build up to several hundred volts. Definitely wakes you up if you get hold of it.

NEVER touch both leads/terminals of an electrolytic cap unless you've shorted those together first.
It's a good idea to use a big resistor, maybe 1000 ohms at 20 watts or so, rather than shorting them directly.

- Leigh

Vivitar 285HV Follow Up:
(I hope this helps others).

This 285 is crazier than my cat.
I tried one last time to reform the capacitor before I looked for a new one for it. I turned the strobe to full power, plugged in it’s SB-4 AC Adapter & walked away for a hour or so. When I came back it was sitting there running!

I have test fired it on & off camera fifty times or more, it’s working like nothing was ever wrong. After trying this reform several times over 3-4 days it is now running. If you have this problem with a strobe, be persistent trying to reform the capacitor. This strobe quit working about 10 years ago….

Thanks for your thoughts Leigh.
Now I have to try to get my Metz 45 TC-3 running.

Leigh B said:

Hi,

Yes, I've done electronic repair professionally since high school (over 60 years ago).
I was a warranty service station for Novatron studio strobes for a few years.

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Way back long ago, I had a consumer grade Honeywell electronic flash (a.k.a. 'speedlight') that had its power capacitor, and a resistor, and whatever else, fail thereby letting all the magic smoke inside to escape. As my uncle was an electronic tech who had imparted some of his skills to me, I took the flash apart to diagnose and hopefully repair it. The challenge was that I found it hard to find an appropriate Voltage+Capacitance+size capacitor to fit inside. As a mere high school age tinkerer, I did not know if there was any kind of master part book that would allow someone to look up Votage + Capacitance and see dimensional information to aid in the selection of a replacement part. And I didn't want to burden my uncle with finding parts, so I just threw the thing in the trash.

I still have curiosity about that! Can you give insight how a tech finds a suitably sized part to fit in space-limited products?

Makers such as Nippon Chemi-con have online catalogs with dimensional information.

Electrolytic caps will dry out just sitting and old ones can be dead with no hope of reforming. But due to the increased use of switching power supplies, the capacitors available today are much better than those from 20 years ago and should last longer. An "exact" replacement for an old part is probably not available but one just as good or better might be. Digi-Key and Mouser are two distributors who sell in small quantities.

Also, be careful of buying electronic parts on ebay. More often than not they are fakes, esp. when dealing with name-brand stuff like Rubycon, and also when dealing with vendors from the far east. Better off buying from "real" suppliers like those mentioned here.

wiltw said:

Can you give insight how a tech finds a suitably sized part to fit in space-limited products?

Click to expand...

In our modern age, all electronic distributors have search functions on their web pages.

You just do a parametric search using whatever characteristics are important to you.

For example, here's a capacitor page at Mouser (where I buy all my parts):
Dead Link Removed

Look at the selection menus below the "Available Filters" heading.
Those list all the available characteristics.
Note that Mouser has almost 63,000 different parts in this category.

Other good distributors of high-voltage capacitors are:
Digi-Key www.digikey.com (not a very good selection function)
Newark www.newark.com (lets you select max and min values for each characteristic)
Allied Electronics www.alliedelec.com (ancient search function that works if you have patience)

- Leigh

EdSawyer said:

Also, be careful of buying electronic parts on ebay. More often than not they are fakes, esp. when dealing with name-brand stuff like Rubycon, and also when dealing with vendors from the far east. Better off buying from "real" suppliers like those mentioned here.

Click to expand...

I'd say don't bother ordering any brand name (Rubycon, Nippon Chemi-Con, ...) capacitors from China. They're most definitely fake and very bad ones actually. There are many listings where the price is just too good to be true and sure enough, you get what you pay for. Out of curiosity I once bought a 10 pack of 1000μF/16V capacitors (supposedly NCC) for $1 or so, I just wanted to see what kind of junk it is. Of course, the vent type was wrong and it was obvious that somebody was sleeving the worst no-name capacitors available. The terminals were even thin and dull - somewhat corroded.

Follow Up on Metz 45 CT-3:
Yes, this strobe now works.
(Hope this info helps someone).

Hard to believe my old Metz 45 CT-3 is also running.
I did the same thing to reform this capacitor over a couple of days.
The strobe sat for an hour or more today with the power on, & it started working.
I realize that any old strobe might die again when it want’s to.

One thing I did to both strobes…….
Was to use a “Abrasive Ink Eraser” on every contact I could find without opening the unit.

The eraser I used was similar to this link.

https://www.amazon.com/Castell-Fabe...&sr=8-1&keywords=typewriter+eraser+with+brush

kmphoto, I've seen similar behavior out of a camera with a electronic controlled shutter. I stuck new batteries in-wouldn't fire. Put it aside and went and washed my car and came back...suddenly it'd fire about 3 times before it'd quit working again. I had a feeling it was a cap for some reason, so I left it on and cocked overnight. Worked fine the next day-had to put 2 more new batteries in it,but it's worked just fine ever since.