Graflex.org Forum Index Graflex.org
Get help with your Graflex questions here
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

please help me identify this electronic bit on my SuperGraph

 
Post new topic   Reply to topic    Graflex.org Forum Index -> Speed Graphic Help
View previous topic :: View next topic  
Author Message
howardpyle



Joined: 17 Jan 2005
Posts: 5
Location: nyc

PostPosted: Wed Dec 21, 2005 5:11 pm    Post subject: Reply with quote

Hi all,
I'm trying to troubleshoot why the electronic flash on my Super Graphic (via the sync port on the body) is very unreliable. I'm trying to trace where it might be messing up and I need help identifying the item circled in white in this image on the back of my lensboard:
http://www.processlab.com/images/graflex-back.jpg

is it a transistor? a solenoid? Could this item be part of my problem?

The flashposts on the shutter are connected to this item on the back of the lensboard. I understand that the lensboard itself has contects built into it that then send the sync current back into the body...

any help would be greatly appreciated.

thanks -howard
Back to top
View user's profile Send private message Visit poster's website
RichS



Joined: 18 Oct 2001
Posts: 1468
Location: South of Rochester, NY

PostPosted: Wed Dec 21, 2005 6:41 pm    Post subject: Reply with quote

From the looks of the screw at the top and that back plate, I'd have to say this is a user modifed board? And I don't see the flash contacts? Hmm, did you take this pic through the back of the camera?

Anyway, that thing is a capacitor. I've never seen one on a Super board.

Are you trying to pop electric flash or bulbs?

I can't read the value on the capcitor, but no matter what size I would think it would interfere with either electric or bulb flash. At best, it would cause a small deley in firing the flash.

If it was mine, I would remove it and see what happens.

As far as reliable flash contacts on a Super, there are a few points that should be checked and cleaned.

On the back-top of the lens board are two contact points. These should be cleaned with something like a pencil eraser. If you look to where the board mounts to the camera, there are corrosponding contact points inside the front standard. Also to be cleaned.

Then there's the plug and socket. The plug can be cleaned but the socket would be tuff...

The cable itself may be suspect, especially if it's a Graphic original. The two I have here used real rubber as wire insulators. Real rubber had a high sulfur cotent and corroded things like wire and it gets very brittle after so many years. The combination makes for broken wires if it is flexed...

If you search the forum, you can find a message left by me describing how I made my own flash cord for the Super.

If removing the capacitor and cleaning the contacts doesn't fix it, try the cable. If you have a ohm meter, this is the easy way. If not, you could jury-rig a battery and flashlight bulb through the individual wires to see if they lose contact when flexed.

If all of this doesn't help, then maybe another pic of the back of the board? Trying to figure out when it doesn't work (cord in certain position)? Testing the shutter itself... There's a lot of variables.

There's also a very slim chance the wires running through the bellows and bodey of the camera are bad. That would need testing with an ohm meter.

Good luck!

Back to top
View user's profile Send private message Send e-mail Visit poster's website
howardpyle



Joined: 17 Jan 2005
Posts: 5
Location: nyc

PostPosted: Wed Dec 21, 2005 7:26 pm    Post subject: Reply with quote

Thanks so much for the detailed response! I'll try your suggestions and post the results.
thanks -howard
Back to top
View user's profile Send private message Visit poster's website
howardpyle



Joined: 17 Jan 2005
Posts: 5
Location: nyc

PostPosted: Thu Dec 22, 2005 11:32 pm    Post subject: Reply with quote

Ok - so I've removed the capacitor from the rear of the lensboard and the flash via the body terminal works flawlessly now!

why on earth would it be there in the first place? to store a charge? that doesn't make a lot of sense as the shutter needs to be cocked everytime and thus no battery charge time...

Hmm!
Back to top
View user's profile Send private message Visit poster's website
45PSS



Joined: 28 Sep 2001
Posts: 4081
Location: Mid Peninsula, Ca.

PostPosted: Fri Dec 23, 2005 2:57 am    Post subject: Reply with quote





[ This Message was edited by: 45PSS on 2005-12-24 19:24 ]
Back to top
View user's profile Send private message Visit poster's website
JBish130



Joined: 20 Oct 2004
Posts: 27
Location: Eastern US

PostPosted: Fri Dec 23, 2005 7:00 am    Post subject: Reply with quote

Capacitors are often used to 'smooth' a signal (think somewhat erratic power going in, smooth going out); or like a valve to take the peak off of a spike in power.

This isn't something that someone would 'just put' into their circuit. This would be installed by someone who was familiar with what they were doing. Most people wouldn't know what a capacitor is, why or how it's used.

Most likely as mentioned, used to take the spike out of high voltage electronic flash. This would help save the contacts inside the shutter; to keep them from arcing/burning.

That's my take on it anyway...

_________________
Jeff Bishop

"It's light and nothing more."
Back to top
View user's profile Send private message Send e-mail Visit poster's website
RichS



Joined: 18 Oct 2001
Posts: 1468
Location: South of Rochester, NY

PostPosted: Fri Dec 23, 2005 7:32 am    Post subject: Reply with quote

Well, maybe I'm just in a contrary mood tonight? But I'll just add a few thoughts here...

With the capacitor across the termicals as in the photo, it will not smooth out any spikes or alleviate any current through the flash contacts. It will however cause a higher current to flow through the flash contacts making them wear out even faster...

Take this idea to an extreme. Replace that little cap with a 1000MF-600V cap. While the flash is charging up, so is the cap. When the shutter is finally fired, there would be enough current available from the cap to explode the shutter as the flash contacts short the terminals the cap is connected to. It's like opening up an electronic flash after it's charged and shorting out the big caps with a screw driver. This little cap does the same thing but on a smaller scale.

I would not recommend anyone place a cap across the flash terminals as this board had. Sure, the person who did t may have known what they were doing, but _we_ don't know what they were doing!

Now, second case. If this was set up for flash bulbs, the cap would charge up when the battery case was connected. When the shutter was triggered, the current would then flow through the terminals and through the bulb. A little extra current here from the cap might be helpful. Personally, I doubt a cap that small would help...

No matter which type of flash is used, the net affect is a higher current flowing through the switch when it makes contact at shutter firing. In modern electronic flashes, this would all not make much difference. But in bulb flashes or old electronic types, it would...

Back to top
View user's profile Send private message Send e-mail Visit poster's website
alecj



Joined: 09 May 2001
Posts: 853
Location: Alabama

PostPosted: Sat Dec 24, 2005 3:33 pm    Post subject: Reply with quote

I suspect it was added to aid multiple bulb exposures. That's not the way Graflex suggested doing it, from the description, it probably worked - at a price of shutter contacts. You'd better check them at some point.

Using a setup like that would not have required fast shutter speeds, so sync at the higher speeds wouldn't matter.

[ This Message was edited by: alecj on 2005-12-24 07:35 ]
Back to top
View user's profile Send private message
howardpyle



Joined: 17 Jan 2005
Posts: 5
Location: nyc

PostPosted: Thu Dec 29, 2005 10:23 pm    Post subject: Reply with quote

Hi there - interesting reseponses!
an update on the super graphic with the mystery capacitor: I removed the capacitor and got some good inital results. However, I was shooting with it over the holiday and found that I could only shoot twice then it wouldn't trigger the strobe again (again, I'm using a connection via the flash sync in the body).

One thing that did work was to hit the shutter button on the body - even without the lens cocked, the flash would go off when I did this! Once I tripped the shutter on the body, I would have two more times where tripping the shutter on the lens would pop the flash via the body.

A side note that is perhaps related: I bought a repair manual for the super+speed graphics on ebay and discovered there is a 2nd Solenoid just below the lens board on these cameras! It's hidden beneath the metal plate just below the lens board. In the manual, there's nothing about the capacitor...

I think for simplicity sake, I'm just going to trip the flash from the bi post sync on the shutter itself - the manual clearly shows a connection solenoids for body flash sync. Also, it mentions capacitors but doesn't show where they are or describe their function...

thanks -howard
Back to top
View user's profile Send private message Visit poster's website
RichS



Joined: 18 Oct 2001
Posts: 1468
Location: South of Rochester, NY

PostPosted: Fri Dec 30, 2005 6:38 am    Post subject: Reply with quote

Howard,

You may want to take a closer look through that manual and trace the wiring.

The solenoid in the front standard is only used to pull down the shutter release mechamism. It has nothing to do with the flash.

The capacitors mentioned are inside the top rangefinder and are only used to store power to fire the solenoid in the front standard.

The wiring for the flash to the body connector is straight from the two connectors on the front standard right to the body connector. There is no switch or solenoid involved. You can hook up your flash, take off the lens board, jump those two connectors with a paper clip and fire the flash. That's basically all the shutter does when you trigger it. A tiny switch inside the shutter closes when triggered and shorts out thos two connectors through the bi-post pins. Same thing, with the flah connected, you can jump the bi-post pins and fire the flash.

Someone else had a problem of being able to fire the flash once or twice, very similar to your problem. I have no idea what words to use as a search, but it may be worth a try. My poor memory is telling me that it turned out to be dirty switch connections inside the shutter? I could be wrong about that?

A simple test would be to have everything set up to shoot a flash shot, then simply jump the bi-post connectors on the front 3 or more times in a row. If the flash fires, there's nothing wrong with the camera. Then do the same thing with the shutter. Use either the electric body switch or the mechanical one right on the shutter and see what happens. I would bet that it works by shorting ut the bi-post pins...

Good luck with it...


_________________
----------------------------------------
"Ya just can't have too many GVIIs"
----------------------------------------
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    Graflex.org Forum Index -> Speed Graphic Help All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group