View Full Version : Compur electronic 5FS shutter's measures

Marco Annaratone
13-Nov-2017, 03:39
Looking to replace my Compur electronic 5FS with a Compound V I checked the measures of the former.

First the front and rear inside diameters _are_ different. While the rear is more or less 82.5mm - and hence most likely the 82.77 of the Compound V that Ole reports in this link (http://www.largeformatphotography.info/forum/showthread.php?23904-Compound-shutter-sizes) - the front has a diameter of about 85.5mm. The tube length of the 5FS I have is about 49mm.

This 5FS is coming with an Apo-Lanthar 300mm mounted on it. However, there is an adapter ring that screws on the front of the shutter that changes the measurements as follows:

1. It reduces the diameter from ~85.5mm to ~82.5mm
2. Extends the length of the tube to 60m.

This tells me that the two Apo-Lanthar cells should be mounted without any modification on a Compound V. In fact, it seems clear that they were produced for a Compound V and Compur (or some metalwork shop) produced the ring adapter so that a 5FS could be used.

What I do not know though - a company data sheet would be most useful - is whether these two measurements, i.e., front diameter and tube length - are truly representative of a "standard" 5FS or are those of my specific sample.

Marco Annaratone
13-Nov-2017, 04:06
I add a couple of images of the inside of the shutter and the control box. It is pretty clear why nobody wants to touch this shutter, the amount of electro-mechanical contraptions is mind-boggling...

The two PCBs, for instance, talk to each other via those vertical gold forks that must be insert one into the other by sandwiching the two boards before putting them back into the plastic case. The two one-of-a-kind multi-pole plugs of the connecting cable (not shown in the pictures) will eventually tend to "dance" inside the female receptacles after many years, thus creating all sorts of on-off problems.

Moreover, the connection between the six 1.5V batteries and the electronics is bound to create all sorts of problems - it is based on copper plates that when you close the control box after you replaced the batteries shall get in contact (and you cannot see if that happens or not, of course) with some prongs of the PCB).

The PCB on the right is all passive and there are no capacitors. Two big resistor ladders, pretty much.

The PCB on the left has some electrolytic capacitors, that I replaced with new ones, the equivalent can be found easily. In terms of active devices there are at least two that can no longer be sourced. In the sense that equivalent can be found but only with a different pin-out, so some tricky (and ugly) surgery needs to be done on the PCB. All the the other ones (about six or seven, I do not remember) can still be sourced.

Bottom line: every time there is a problem the issue is (a) the electronic? (b) some contact in the cable connecting shutter and control box? (c) some contact in one of the two rotary switches (totally mechanical, I have not shown them) that select time and f/stop? (d) have I closed the control box correctly after replacing the batteries?

In the upper right corner there is the mechanism of the time shutter. The two-prong track at the bottom instead controls the opening of the second shutter, the f/stop shutter. That's pretty much as far as I was able to go.



Paul Ewins
13-Nov-2017, 15:53

Diagram of the 5s from the Compur Electronic Shutter repair manual which covers all of the variants. (available on ebay - https://www.ebay.com.au/itm/Compur-Electronic-Shutter-Repair-Manual-c1966-1970/372052140053?hash=item56a0092015:g:iKcAAOxyY3ZR0FB5)

15-Nov-2017, 09:25
I own two different versions of this shutter.

The version described in this thread with the control box and the PCB's inside the shutter.

Then there is a version were there are only two solenoids in the shutter. Connection to the control box is through a cable terminated in a round connector. That version requires a 24V pulse to open and another 24 pulse to close the shutter.

The mechanical aspects of the shutter are same.



Rudi A.