View Full Version : Do compur electronic shutters work with out batteries

S. Preston Jones
20-May-2004, 08:36
Can any one who has used one of these shutters tell me if there is a way to get the Compur electronic shutter to work with out a battery. I do not care about the so called consistency of speed that is supposed to come with battery use. Has any one made these shutters work or do I have to put the lens in another shutter?

Jim Galli
20-May-2004, 11:23
Without a battery it will default to the fastest speed at all settings.

Michael S. Briggs
20-May-2004, 12:01
If the reason that the shutter doesn't work is that you don't have a battery, then the best plan is to buy a battery. The batteries for the Compur electronic #3 are still available. See http://www.largeformatphotography.info/lfforum/topic/496852.html.
One source, as I mentioned there, is Radio Shack. They still have it listed on their website.

Arne Croell
20-May-2004, 13:29
As Jim wrote, they default to the fastest speed; which one, depends on the shutter size (1 or 3). The same is true for the Copal electric. Note that the large Compur 5 electronic with the external command unit won't work at all without batteries.

S. Preston Jones
20-May-2004, 15:39
The lens I bought on ebay does not have the battery compartment. I should get the lens soon. I also found a battery compartment on ebay and when I get the lens and battery compartment I will get the battery and try thr combo. If that fails, I do have an unused Copal #3 and will be able to change the shutter. Thanks for your help.

Emmanuel BIGLER
21-May-2004, 03:47
A friend of mine and LF aficionado has been successful connecting an electronic Compur shutter to a 4.5 volt battery ; any kind should work. In Europe, flat 4.5V batteries used to be the most popular for pocket lights, they are gradually replaced by stacks of AA cells. You do not need the special battery size and battery compartment if you accept to live with something a bit bulky or crude ;-)
Personnaly I would use a stack of 3 AAA-size 1.5V batteries to keep the attachment as small as possible ; smaller 1.5V batteries could be possible of course as long as you keep the 4.5V output, but the smaller the battery, the smaller the capacity will be. Battery holders for 1,2, 3,... etc AA or AAA-size batteries can be found from most retailers in electronic components.
Beware however to the right '+' '-' polarity of the shutter terminals. Be prepared as well that the shutter could be out of order, if it has not been demonstrated in front of you before.

Arne Croell
21-May-2004, 08:13
Prontor still sells the battery compartments as replacements - at least for the Compur electronic 3 (I bought one a few weeks ago).

Struan Gray
21-May-2004, 14:15
I bought a 'replacement' sold by a UK store consisting of three small 1.5 V batteries held in a stack by heat-shrink tubing. It fits the battery compartment on my Compur electronic 1 shutter perfectly. Until it arrived, I used a 3 Volt CR2 battery with an Al foil spacer to make up the length. When the replacement dies I'll go back to the jury rig.

When I was researching this, someone (Arne, was it you?) said that the Compur electronic shutters would work on any voltage between 2.5 V and 6 V. Using a laboratory photoreceiver and an oscilloscope, I could detect no difference in the timed speeds between the CR2 at 3V and the replacement 4.5 V battery. The electronics only does the shutter timing - the blades are cocked manually and power to move them comes from a spring - so it doesn't surprise me that a wide variety of input voltages will work.

I'd be interested if anyone has found a commonly-available piece of electronics that fits the prongs on the side of the shutter. The battery compartment is always getting in the way, and making something smaller is on my to do list.

brad vance
6-Jun-2004, 22:39
I just got a Schneider 240/420 in mint condition and it is mounted in a Compur electronic 3 shutter. This is the first time one of this breed has fallen into my hands and I am at a loss as to where the batteries go. The box has written in the top, "Mallory px21", and I ausume this has to do with the lens, but I am lost after that. Do I need another accessory to be able to fire the shutter at all speeds? As it is, all the speeds fire the same.

Any info will be greatly appreaciated.

Many thanks,


Michael S. Briggs
6-Jun-2004, 23:40
Brad, as Jim states above, without a battery, the speeds of the Compur Electronic 3 are unregulated and all run at the fastest possible speed. Since all speeds are firing the same on your shutter, either it is broken, has a dead battery, or no battery at all.

The battery fits into a brown cylindrical attachement that fits onto two metal prongs on the side of the shutter. Does your shutter have this compartment -- you can't miss it? If not, Arne states above that replacements are still available from Prontor.

The "Mallory px21" written on the box is the brand and name of one type of battery that will work. See http://largeformatphotography.info/lfforum/topic/498583.html for info on equivalent, currently available batteries. Or, as Struan described, you can rig up a substitute.

If the shutter was sold without batttery or compartment, probably the seller had no way to know whether the shutter was working. You might want to consider returning the shutter, or asking for a longer return period to allow you to test the shutter, or a partial refund for the cost of buying the compartment, etc.

brad vance
7-Jun-2004, 11:18
Many thanks for your reply Michael. No, it does not have the attachment you mention; so, it seems my best bet is going to be getting one from Prontor.