Compur Shutter and Strobe firing at slow shutter speeds

[NCAmother]

I have a compur 2 shutter firing into profoto strobes question: When dropping my shutter speed to slower than 1/30s, the flash is triggered multiple times. I.E. the flash will fire twice wether at 1/30s or 1 second. Is this normal? Am I able to drag the shutter while using strobe? Thanks,
Nate

[Neal Chaves]

The shutter contacts are bouncing. They close, firing your strobe, but then bounce open again and because your new strobe is ready almost immediately, unlike older power packs, it fires again when the contacts close again to stay closed as long as the shutter is open. This is quite common with Compurs and Seikos. There is no demand for my Ghostmaster Flash Fire Control System for Leaf Shutter Cameras so I no longer produce them. A "bounce free switch" circuit in these pretty well tamed this problem and added many other capabilities. You will learn a lot from my now public domain patent.
http://www.freepatentsonline.com/5530320.html

[NCAmother]

The shutter contacts are bouncing. They close, firing your strobe, but then bounce open again and because your new strobe is ready almost immediately, unlike older power packs, it fires again when the contacts close again to stay closed as long as the shutter is open. This is quite common with Compurs and Seikos. There is no demand for my Ghostmaster Flash Fire Control System for Leaf Shutter Cameras so I no longer produce them. A "bounce free switch" circuit in these pretty well tamed this problem and added many other capabilities. You will learn a lot from my now public domain patent.
http://www.freepatentsonline.com/5530320.html

Thank you. I wish I could purchase, was still available. Is there any thing my lens/shutter repair woman (Flutotscamera)can do to eliminate this problem?

[gnd2]

Think I need something like that for my Packard shutter, it's giving me multiple flashes too.

[Neal Chaves]

You don't need all the functions of the Ghostmaster, just a bounce-free circuit in the sync connection. I'll get out the books tomorrow and find a schematic for a circuit that will work. It's going to tame the double pops, but will probably limit the top sync speed to 1/125 as on the Ghostmaster. The Compur 2 is kind of unique in that it operates on B from the cable release without having to cock the shutter each time. Have you tried using B? It might not have the bounce problem. Because I have seen this on new shutters, I doubt a CLA will change anything.

Packards I have seen use a common micro switch. Some of these are snap action, some are plain SPST type like a push button. I can see where the snap action type might be prone to bouncing.

[Neal Chaves]

https://circuitdigest.com/electronic-circuits/what-is-switch-bouncing-and-how-to-prevent-it-using-debounce-circuit

At the above link I found there are now ICs you can buy to rig up a switch debouncer very easily if you have some electronic skills, but I had a better idea come to me overnight. Just sync through an inexpensive radio trigger set. I bought the ones I am using for the Open Studio workshops we used to have before sheltering in place for $5 each at Roberts. These things won't sync at over 1/125 sec. so they are not going pop on a bounce.

[LabRat]

Clean the contacts first... If there is a imperfect connection when internal contacts are closed, they can miss or multiple fire... Most old plated contacts will be oxidized...

Steve K

[NCAmother]

https://circuitdigest.com/electronic-circuits/what-is-switch-bouncing-and-how-to-prevent-it-using-debounce-circuit

At the above link I found there are now ICs you can buy to rig up a switch debouncer very easily if you have some electronic skills, but I had a better idea come to me overnight. Just sync through an inexpensive radio trigger set. I bought the ones I am using for the Open Studio workshops we used to have before sheltering in place for $5 each at Roberts. These things won't sync at over 1/125 sec. so they are not going pop on a bounce.

Hi Neal, I just picked up the GhostFlash off of eBay, I got lucky it was listed. I’ll keep you updated on how things work out

[Neal Chaves]

Hi Neal, I just picked up the GhostFlash off of eBay, I got lucky it was listed. I’ll keep you updated on how things work out

If you didn't get an instruction book with it, let me know.

[NCAmother]

If you didn't get an instruction book with it, let me know.

Thanks it came in yesterday. I’m very pleased as it for the most part resolved the multi flash problem on instant mode, however on delay mode I still get the multi flash at 1/5 second and slower. On B it wil flash just once which is great. I’m running a Compur shutter to pc/mono plug to GhostMaster to pc outlet to remote hotshoe with profoto remote trigger to profoto B10 strobe.

[Neal Chaves]

As it is mentioned in the instruction book, if you have one, the Ghostmaster doesn't need much power at all to operate. Triggering on a bounce at slow shutter speeds can frequently be stopped by using a "dead" 9V battery. Try it. I hope you experiment with the other capabilities of the Ghostmaster and share the results here on the forum.

Neal