IIIg flash sync failure

[qqphot]

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I have two Leica IIIg bodies, both with the same problem. On either of the flash sync shutter speed positions denoted by the little arrows, the flash isn't fired at all.  On other speeds it fires, but of course isn't correctly synchronized for electronic flash.

One of the cameras' flash sync used to work fine, but came back from service (for a different problem) with sync no longer working.

The other one has never had working sync since I've had it.

The similarity leads me to think this is not exactly a random issue, but I can't follow the diagrams well enough to understand what's going on or how it could be repaired.  Anyone recognize this problem?

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[jerzy]

maybe this will help... In any case you will need to take off the top cover, you will need as well soldering iron. Drawings are from repair manual, photos are mine. Wheel 1 rotates when shutter runs. One of the inserts (like below 1) shall touch then lever 2 which closes the contacts 3. If the wires are soldered in opposite manner (see drawing like it shall be) than flash will not fire at all. If contacts 2 and 3 are not positioned correctly cintacts will not close. And if inserts are not in their places or the spring is wrong they will not close contacts.  So there are few possibilities, even the flash contact itself may be deffective (for flash not working at all)

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Edited September 8, 2022 by jerzy

[qqphot]

Since it fires on some random speed settings but not the arrow positions, I suppose the wiring to the contacts is OK but probably the inserts are assembled in the wrong positions. Once I get over my fear of opening the top cover I will have to check this out.  Thank you for the very helpful information!

[Michael Geschlecht]

On 9/8/2022 at 5:22 PM, qqphot said:

Since it fires on some random speed settings but not the arrow positions, I suppose the wiring to the contacts is OK but probably the inserts are assembled in the wrong positions. Once I get over my fear of opening the top cover I will have to check this out.  Thank you for the very helpful information!

Hello qqphot,

Welcome to the Forum.

Are you setting the little lightning bolts to their proper positions in order for an electronic flash to operate properly?

There is a IIIg instruction book, including flash data, at the top of this page in the "Leica WIKI" in the "English" section. The English language WIKI has IIIg instructions written both in English & in German.

Best Regards,

Michael

Edited September 24, 2022 by Michael Geschlecht

[qqphot]

On 9/23/2022 at 5:43 PM, Michael Geschlecht said:

Hello qqphot,

Welcome to the Forum.

Are you setting the little lightning bolts to their proper positions in order for an electronic flash to operate properly?

There is a IIIg instruction book, including flash data, at the top of this page in the "Leica WIKI" in the "English" section. The English language WIKI has IIIg instructions written both in English & in German.

Best Regards,

Michael

Thank you. Yes, the problem is that the flash does not fire at all when set to the "lightning bolt" positions. On other speeds it fires, but of course isn't correctly synchronized for electronic flash.

[qqphot]

I thought I'd update here in case anyone else stumbles across this, as I resolved it sort of by accident. After some use the speed setting dial on this camera developed some play and eventually would spin freely. I removed the three grub screws securing the dial, and found that the flanged collar beneath it had itself loosened to the point that it was rotating freely on the speed setting shaft and applying no downward pressure on the spring below. I returned it to its correct position and re-secured the collar's own grub screws, found the correct position for the dial and re-secured that. This resolved the loose speed dial and mysteriously also the non-functioning flash sync. In retrospect it had probably been loosening for some time.

Edited October 2, 2022 by qqphot

[Leicabimmer]

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Thanks Jerzy for the explanation. I am having the same issue with my 111F in that the flash fires continually when plugged into the synch port. After removing the cover it looks like the contact surfaces are closed(making contact) all of the time. Unfortunately the illustrations that might help me unravel this mystery are not showing up on my end for some reason. Is it possible to reload them or PM me with the illustration? Thanks!

[jerzy]

Hi, I do not remeber what photos were there but they would  not help you anyhow, flash sync is done differently in IIIf and IIIg.
I understand that in your camera flash fores immediately after you plug in, regardless if release button is pressed or not, reghardless what speed is set and regardless how the flash contacts are set.
This means that there is electrical shortcut between middle point of the flash socket and ground (chassis). 

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There are 2 switches within flsh sync circuitry, both must be closed in order to fire the flash . One switch is closed when you press release button (1), the second when the shutter runs (2).

In your case flash fires immediately and constantly and this means that either soldering point touches the chasis or isolation on switch 1 is deffective.
You will need to remove accessory shoe (4 screws) and check the soldering point - it must not touch the chassis. Desolder it, leave the wire free, plug flash in. If it fires than the flash socket is deffective. Otherwise there is something wrong with  contacts 1. You will need to take top cover off and check isolation. Pawl x goes down when you press release button., Under the pawl, on brass contact there must be an isolation ringf - pawl cannot touch brass directly, pawl is electrically ground.

If the symptoms are different, i.e. flash fires only at specific setting of speed dial and/or flash contact number than the problem is not there where I described it.

[jankap]

Is this the problem perhaps? Modern flash devices are made for low voltage. Devices from the time, where IIIf were used, burn the sensors of modern cameras. 

[Anbaric]

13 hours ago, jankap said:

Is this the problem perhaps? Modern flash devices are made for low voltage. Devices from the time, where IIIf were used, burn the sensors of modern cameras. 

The IIIg just closes a circuit. The voltage shouldn't matter (within reason). Even a relatively high voltage flash won't hurt the camera, and a modern low voltage flash should be triggered like any other. Here is sounds like there is a short circuit.

[Leicabimmer]

Jerzy- Thank you for your explanation and photos of the flash synch circuit. At the very least it illustrates the configuration of the contact switches. The pictures in question you uploaded were from 8 Sept 2022. If you can see them on your end perhaps you could re-upload them or screen grab them for me and others. Again thank you for your input!

[Leicabimmer]

Do you have a lower view of the circuit from directly behind the camera so I can see where the gap is and how wide it needs to be?

[jerzy]

vor 11 Stunden schrieb Leicabimmer:

perhaps you could re-upload them

here they are, but as mentioned before - this is IIIg and is different than IIIf

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[jerzy]

vor 8 Stunden schrieb Leicabimmer:

Do you have a lower view of the circuit from directly behind the camera so I can see where the gap is and how wide it needs to be?

no, I do not have a photo. How big the gap is is  not critical, there must be gap when release  button is up, gap must close when you press release but before the shuttetr runs, otherwise flash will not fire (in proper working Leica).
Here you have drawing from repair manual showing componentes of the switch. Switch has 2 brass contacts (...670 and ...672) with isolatioon layers (672 and 673) between the chassis and both contacts. Green arrow show the place where an isolation ring is placed and this is as well where pawl X from previous posting is touching the contact. In order to check it you will need to take off top cover, so why not to check before flash contact itself as I described earlier

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Edited August 12, 2024 by jerzy

[Leicabimmer]

Wow wow wow Jerzy thanks so much! This is like finding the Holy Grail for me. I've been searching for this info for years. I'll let you know if I get this sorted.