Vivitar Flash Gun

I have just dug out my old Vivitar 2500 Flash to try with my Canon Powershot SX10IS.

It was working and I was getting used to it and then it failed. Tried fresh batteries and it is erratic. I hear it whining as it charges but the ready light isn't coming on. If I press the manual button I can see a faint flicker in the flash tube and the green light flickers.

Has anyone got any ideas about how these fail?

Reply to
John
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The first thing to try is replace the large capacitor. If left for a long time electrolytic capacitors begin to leak (electricity that is) which would explain the symptoms you have. They're cheap so it's worth a shot.

Another Dave

Reply to
Another Dave

Marked as 380 micro farads 350v "for Photo Flash"

40mm long by 25mm diam.

I guess it dates from about 1980

Reply to
John

Possibly just slightly corroded battery contacts - so try cleaning those first. More usually though it is the large high voltage electrolytic capacitor which acts as the tubes energy store develops a leak (partial short circuit). If unused for years it needs "reforming" before being put back into use.

Replacing them isn't too difficult if you can solder but beware - even a leaky capacitor of that voltage (about 300VDC) and size (about

800uF) can administer a very large shock so ensure everything is discharged before playing with it.

Finding a replacement of the right dimensions and characteristics may not be simple. Normal electrolytic capacitors don't survive the rather brutal regime of a flash gun too well and a photoflash rated capacitor may be difficult to find. That said if you don't use it too much a standard capacitor will work - it just won't have a very long life.

There are some Vivitar 2000 series photos at

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will give you some idea of the layout.

By the way - be careful using old flashguns on modern cameras. Many cameras flash trigger circuits on the top hotshoe are only safe at low voltage (5V or so) and some old flashguns can have several hundred volts on the trigger connector.

The Vivitar 2500 has about 12V on the shoe so is a bit iffy.

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Reply to
Peter Parry

Crikey - I just touched an insulated screwdriver across the terminals - hell of a flash and bang. Glad it was insulated.

Nothing has changed (except my screwdriver has burn marks.) Glad I knew enough to be careful whilst being reckless!

Reply to
John

John wrote on 03/01/2011 :

The capacitor is the most likely to have failed - often happens to long disused electronics.

Reply to
Harry Bloomfield

As my need was somewhat speculative then I think I will avoid any risk to the camera and forget about the flashgun. I got a few useless pictures of my study whilst it was working - so it had no immediate damaging effect on the camera. Not worth the risk though - and it looks like getting a new capacitor may be difficult.

At least I took it apart and had a look inside.

Reply to
John

q.v. thread about microwave lamp!

Reply to
Skipweasel

TBH I was initially surprised you hadn't blown the crap out of the Canon, as I thought the 2500 was old enough to have it's full flash voltage across the trigger terminals; but Google suggests it's around

13-14V for the 2500 so presumably that's within the Canon's limits.
Reply to
airsmoothed

TBH I was initially surprised you hadn't blown the crap out of the Canon, as I thought the 2500 was old enough to have it's full flash voltage across the trigger terminals; but Google suggests it's around

13-14V for the 2500 so presumably that's within the Canon's limits.

I looked through the manual but couldn't find any limits. I will steer clear though. I had it in mind for a once a year large group photo. I'll forget to take my camera and let someone else do it!

Reply to
John

I _am_ guessing, but I'd go for an HT leak somewhere. Take all the covers off and run it in the dark and look for sparks. Could be leaky capacitors.

Andy

Reply to
Andy Champ

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