Question for those who are privy to the idiosycrasies of electronics (help!)

[David Lyga]

I recently acquired a Vivitar XC-3 (Cosina CSL) that was manufactured in the late 1970s. It has an electronic shutter from 4 sec to 1/1000, plus a mechanical shutter for Bulb and 'M' (1/50). Its film advance is one of the smoothest ever and it looks great. There is a frustrating problem that I think I cannot fix, but want to know, anyway, what causes this dilemma.

If the electronic shutter has not been fired for some time (from 30 minutes to days), it initially caps, which, in this case, acts as if there is not power in the camera (this, despite the fact that the LED meter is fully operable, always). After a few firings, the electronic shutter begins to work, accurately.

This situation is determined by the time that the shutter was not used. For example, if I do not fire the shutter for, say 20 to 30 minutes, one or two firings is necessary to activate an accurate electronic shutter. If I do not fire the shutter for, say, twelve hours, like, for example, overnight, it takes up to seven or eight firings to make the electronic shutter act accurately. In all cases, once it begins to fire accurately, as long as I keep no pause more than about 15 minutes, it continues to fire accurately.

The electronic shutter mechanism seems to need an electronic 'boot': that's all I can say, because I do not understand these things well. It seems that its 'capacitor' needs a revitalization of 'lost' power through not using it for that short time. The mechanical shutter is never a problem, but you can see how frustrating this problem is because, with film loaded, one does not know if the shutter is really firing, because faster speeds sound just like the 'curtain-capped speed'.

Please don't suggest that I visit an electronics store and 'buy a certain capacitor': I am too stupid to know how to install it. If that is the only answer, state it, but know, in advance, that all you will be doing is informing me of the problem (yes, this also helps) and not actually solving the problem. Thank you. - David Lyga


Butkus manual: http://www.cameramanuals.org/pdf_files/vivitar_xc-3.pdf

 

[BrianShaw]

Hi David. Have you ruled out a mechanical or lubrication issue?

 

[bdial]

The release button likely operates some sort of switch. If you're lucky the contacts may be exposed and you can try cleaning them, assuming you can get the top cover off.
As Brian suggests, there may be some sort of mechanical cause as well, getting the cover off may help with diagnoses. For example, if you can actuate the switch directly and the camera works reliably, then there may be some sort of mechanical problem with the release button.

 

[David Lyga]

Hi David. Have you ruled out a mechanical or lubrication issue?

Utterly ruled out. - David Lyga

 

[David Lyga]

The release button likely operates some sort of switch. If you're lucky the contacts may be exposed and you can try cleaning them, assuming you can get the top cover off.
As Brian suggests, there may be some sort of mechanical cause as well, getting the cover off may help with diagnoses. For example, if you can actuate the switch directly and the camera works reliably, then there may be some sort of mechanical problem with the release button.

No, This is why I stated that the meter LED works perfectly at all times, Power delivery is not an issue. I had the top off and this is a very clean camera. A 'capacitor' is not 'holding' the shutter power. The mechanics are fine with this very clean and 'new' camera. - David Lyga

 

[DWThomas]

I second Brian's question. Even "electronic" shutters, at least in that era, are mostly mechanical with the timing controlled by electronics. The actual supply of energy to move the mechanics may be provided by solenoids of some sort that are battery dependent. (In some cameras -- Bronica SQ series for example, that slug of power is provided by stored energy from a spring tensioned by the film winding.)

Anyway, if lubricant is congealed or an accumulation of fuzz has built up in the mechanics, electronics won't overcome it. I've no idea what's in that specific camera, but I've seen exploded views of things like my Canon A-1 and they are full of flexible printed circuitry folded up and running every which way. It's pretty scary to even think about going inside the electronics of such a beast. But I know in the Canon Axx series there is a solenoid that is known to get sticky and misbehave, but I believe it is relatively accessible without diving in very far. If you're lucky, perhaps your new acquisition has something similar.

 

[David Lyga]

Yes, with these, even attempting to remove the prism is fraught with pain and suffering (and, ultimately, defeat). As many cameras as I have cleaned and fixed, I swear that this is NOT a mechanical issue. Something electronic 'dried out' and I will bet that there will be someone aping what I said, originally. Power is not being 'stored' properly. The 'capping' firing is utterly smooth and if I were to freeze this body, the shutter would operate just the same. NO dried lubricant or debris here.

I will also say this: until a few days after I got it a couple of weeks ago, the self timer (electronic, completely, no spring) did the same. It would work, sometimes, initially. NOW it does not work, although its indicator light works perfectly, and it stops when moved its necessary 90 degrees (after cocking the shutter), awaiting its firing. So, even when implemented, when that shutter is fired, the s/t crank immediately moves back into position with no wait time and the shutter fires immediately. Again, there is NO SPRING for that self timer lever: it is ALL electronic. Damn, I like clockwork cameras!!! - David Lyga

 

[btaylor]

You have probably already done it, but try new batteries, from a different source than the ones you already have. In my primary trade we come across this problem frequently, most stuff works just fine but some functions do not and it’s a battery problem. I have purchased plenty of batteries that test bad right out of the box. And all of them in the box are bad. Just a thought before you go too far down the rabbit hole!

 

[shutterfinger]

David, the shutter is mechanical with electronic release. Without a repair manual that has a schematic of the electronics its just guessing. Did you note how many set of contacts were in the shutter switch? Were each bright and shinny?
The timer is likely a chip as is the meter. Timer out 1 energizes solenoid 1 which releases curtain 1 then when the timer runs a specified time output 2 energizes solenoid 2 which releases curtain 2 when all is well.
As others have said solenoid 2 is releasing prematurely due to mechanical wear or other mechanical fault OR the timer chip is bad and after several operational attempts it heals itself and starts working properly. When it has not been used for a while its cold. In the cold state all internal contacts (layers) are not making contact. After a few usages it warms up and the layers start making contact until it cools again. If its the timer chip the only repair is to replace the chip. There may be other electronic components between the timer and solenoid that exhibit similar behavior.

 

[glbeas]

If it is a capacitor problem its an electrolytic capacitor thats dried out. It might need a repair tech to ferret the problem

 

[John Koehrer]

The AE1's had a relay on the bottom that became sticky would revive by cleaning the contact.
Used to use the edge of a dollar bill dampened in alcohol.

 

[David Lyga]

I am intrigued by the fact (pointed out by shutterfinger) that there are TWO separate 'chips' involved here: one for the meter (which works perfectly) and the other for the actual timing mechanism. (There probably is a third for the self-timer.)Yes, other than the timing, the shutter is 'mechanical', as the movement is such. I knew, in advance, that there was no easy fix here, but you have thankfully opened up possibilities for further exploration. I thank you all. And, maybe, I have to potentially admit, that, even though everything looks new, there might be weak connections somewhere. I paid very little for this, but at least I have Bulb and 1/50 mechanical. - David Lyga

 

[grahamp]

Probably a capacitor issue. Behavior that changes with the time power is applied is a strong pointer. You might want to see if the speeds are sane when it is working. If the capacitor is failing it could affect the timing.

 

[David Lyga]

ALL speeds are fine when 'warmed up' (not temperature-wise, just after a few attempts). NOTE: Due to an onerous short-term temp job scoring student exams, I will not be available for a few days (or should I say 'daze'). Thank you all. - David Lyga

 

[Chan Tran]

I second Brian's question. Even "electronic" shutters, at least in that era, are mostly mechanical with the timing controlled by electronics. The actual supply of energy to move the mechanics may be provided by solenoids of some sort that are battery dependent. (In some cameras -- Bronica SQ series for example, that slug of power is provided by stored energy from a spring tensioned by the film winding.)

Anyway, if lubricant is congealed or an accumulation of fuzz has built up in the mechanics, electronics won't overcome it. I've no idea what's in that specific camera, but I've seen exploded views of things like my Canon A-1 and they are full of flexible printed circuitry folded up and running every which way. It's pretty scary to even think about going inside the electronics of such a beast. But I know in the Canon Axx series there is a solenoid that is known to get sticky and misbehave, but I believe it is relatively accessible without diving in very far. If you're lucky, perhaps your new acquisition has something similar.

Even with today's DSLR the shutter is spring powered and only the timing is electronic. However since David didn't have problem with the mechanical speed I think the problem is in the electronic. I have the Nikon FE which has the reversed problem from David camera. The mechanical speed 1/90 always work. Electronically controlled either in A or manual would work for a number of shots rapidly and then stopped working. Switching to 1/90 to reset the camera the electronic shutter would work again.

 

[4season]

Just curious, but do you see any electrolytic capacitors in there? Here's a video showing a Minolta with one such part:

If so, I'd proceed no further until replacing that part.

IME, semiconductors (transistors, diodes, ICs etc) don't generally just "go bad" unless stressed. Not completely unheard of though: Sony had manufacturing difficulties in the early 2000s which caused some of their CCDs to fail over time. But this sort of thing isn't common.

And in the case of a camera that's clean and was properly stored, probably not going to find any issues with faulty connections, but sure, go ahead and do a visual inspection of the soldering, paying particular attention to hand-soldered areas such as where individual wires attach to the circuit boards. Except where battery leakage is involved, not common, but I have encountered a couple of instances where resoldering was needed.

 

[shutterfinger]

I have encountered layer separation type failures in about 1% of all solid state device failures I encountered when servicing electronic equipment. I have had them heal themselves only to fail 100 hours or less of usage later.
David's problem could be a diode or transistor external of the timer chip also.

 

[David Lyga]

Again, thanks for your feedback. I knew that this one would not be a 'quick fix' and 'early' electronics from the 70s can be a bigger problem, I know. Maybe my question will help others and open different avenues of redress into this perplexing issue. My camera was certainly not the first to experience such distress. The electronic self-timer NOW no longer works. But, that is no big deal as I have a mechanical one that screws into the shutter button. What is bad is one never knows (unless on mechanical) if that shutter will allow a picture to be taken. Such a pretty camera and so clean. - David

 

[Pentode]

By the late ‘70s most printed circuit boards were made of epoxy resin and were a lot less susceptible to moisture than earlier ones. Also by then, manufacturers were starting to migrate away from discrete components and toward integrated (proprietary) chips.

That first bit is good news as it makes a board failure unlikely. Still possible but unlikely. The second bit is not so good as it means a bad chip will not be a stock, easy to replace item.

I agree that chips seldom just “go bad” without a good reason. They’re environmentally sealed and pretty well protected. Capacitors, on the other hand, DO just go bad - both electrolytic and film caps can deteriorate just from sitting unused, which makes them the ideal first place to look for trouble and at that point caps were still discrete, easily replaced components.

If I were in your position I’d first replace any electrolytic caps that were visible on the board. Film caps are less likely to be a problem here. If replacing caps doesn’t change anything I suggest finding a donor camera - one with physical damage and working electronics and simply swap boards.