Testing high voltage capacitors

10/15/2010 12:05:43 PMJohn

Hi,

Is there any way to test a high voltage capacitor to see if it's good or not?

It's not for an old radio or amplifier, it's for a flash power pack (for photography). The only one I was able to repair, had a blown cap. Evident....

All capacitor are connected in parallel. The best way is to removed all caps and test them separately. But after, how?

Thank you
John

10/15/2010 1:38:58 PMMarv Nuce

John,
These are very hi voltage caps. Probably several thousand volts storage devices to flash the Xenon tube. Most old cap testers are not capable. Might need a special unit specifically for flash equip, or just replace all if possible.

marv

:Hi,
:
:Is there any way to test a high voltage capacitor to see if it's good or not?
:
:It's not for an old radio or amplifier, it's for a flash power pack (for photography). The only one I was able to repair, had a blown cap. Evident....
:
:All capacitor are connected in parallel. The best way is to removed all caps and test them separately. But after, how?
:
:Thank you
:John
:

10/16/2010 12:08:00 AMEdd

Sir John. . . . .

With having had experience waaaay back to the day of the first flash units and the early day Speed-Lites or Strobonar units, and familiarity with both types . . . I need to initially pose this question.

Now, they were initially using storage capacitors of up to a 2KV rating which dumped into the flash tube, but the desire of portability ended up with vibrator power supplys running from batteries that could power up a DC power supply for charging up low leakage electrolytics in the hundreds of microfarads and at only about an ~ 300-400 VDC rating.

In that latter, and current technology, initiating flash action was left up to the high voltage ionizing voltage fed to an electrode around the peripheral glass of the flash tube.

A trigger transformer produced a multi KV voltage that was af such ampltude that the flash tubes gas ionized and then even the stored 330 + VDC was then be able to immediately flow across that initially created plasma path . . . and then all H**L breaks loose . . . at least, for a couple of milliseconds !

Now the question, after checking the markings on the caps that you have . . . are your caps in question, the old multi KV high voltage units or are they the high capacitance lower voltage units?

If they are the HIGH voltage units I can give a non destructive test procedure for them, or if being of the lower voltage units, the same holds true, but need to which types are involved..

If being the latter, there is also the additional consideration of inactive storage atrophy and the need of their reforming also becomes a factor.

73's de Edd

:John,
:These are very hi voltage caps. Probably several thousand volts storage devices to flash the Xenon tube. Most old cap testers are not capable. Might need a special unit specifically for flash equip, or just replace all if possible.
:
:marv

:
::Hi,
::
::Is there any way to test a high voltage capacitor to see if it's good or not?
::
::It's not for an old radio or amplifier, it's for a flash power pack (for photography). The only one I was able to repair, had a blown cap. Evident....
::
::All capacitor are connected in parallel. The best way is to removed all caps and test them separately. But after, how?
::
::Thank you
::John
::
:

10/16/2010 11:16:45 AMJohn

Well, I don't know much about these flash units, but one is a ASCORLIGHT QC 1000 and 2 other w/o name, but look like to be built the same way (all caps in parallel), from ~1980. I found schematic for the QC 1000 and caps are 1200 uF @ 500 V.

The one I have repaired was a ASCORLIGHT CD 2400. No schematic but the problem was easy to find. One cap was bigger than the others (blown).
Marking on it is:
9-222-0719
(2) 7921L
1902 (don't know how to read this)

I removed it and unit is now working (CD 2400)

That's all I know.

Thanks for help! :)

10/16/2010 1:44:41 PMGeorge

Not sure if this will help or not ...but when I am at a party or wedding I take the film out of those cheap throw-away cammeras and keep the capacitors out of them they are rated at 300-400v at 1500mf Wholy crap when you charge them up you want to have your fingers no-where near them...they create quite a "fire cracker" sound when discharged....

:Well, I don't know much about these flash units, but one is a ASCORLIGHT QC 1000 and 2 other w/o name, but look like to be built the same way (all caps in parallel), from ~1980. I found schematic for the QC 1000 and caps are 1200 uF @ 500 V.
:
:The one I have repaired was a ASCORLIGHT CD 2400. No schematic but the problem was easy to find. One cap was bigger than the others (blown).
:Marking on it is:
:9-222-0719
:(2) 7921L
:1902 (don't know how to read this)
:
:I removed it and unit is now working (CD 2400)
:
:That's all I know.
:
:Thanks for help! :)
:

10/17/2010 11:16:22 AMcodefox

Beware of disposable camera capacitors. They are designed to be used as intended (a few dozen times)and will have a very short service life in other applications.

:Not sure if this will help or not ...but when I am at a party or wedding I take the film out of those cheap throw-away cammeras and keep the capacitors out of them they are rated at 300-400v at 1500mf Wholy crap when you charge them up you want to have your fingers no-where near them...they create quite a "fire cracker" sound when discharged....
:
:
::Well, I don't know much about these flash units, but one is a ASCORLIGHT QC 1000 and 2 other w/o name, but look like to be built the same way (all caps in parallel), from ~1980. I found schematic for the QC 1000 and caps are 1200 uF @ 500 V.
::
::The one I have repaired was a ASCORLIGHT CD 2400. No schematic but the problem was easy to find. One cap was bigger than the others (blown).
::Marking on it is:
::9-222-0719
::(2) 7921L
::1902 (don't know how to read this)
::
::I removed it and unit is now working (CD 2400)
::
::That's all I know.
::
::Thanks for help! :)
::
:

10/23/2010 8:49:21 AMFor Edd...

Hope to have an answer from you about testing my caps. If you have other questions about my power packs, I will try to do my best.

Thanks.

John

12/29/2010 3:55:48 PMJohn... For Edd

Hello, If you have a way to test them, please post it. I think I found something on internet, but will wait until you show me how.

Thanks and happy New Year 2011! :)