Olympus OM-X on/off switch

[jonty]

I'm a passionate single-digit OM camera user and among the 1n, 2n, 2-SP and 4 that I use regularly, I feel like I have the best of all worlds for different styles of shooting. If there's one annoyance during use, it's that the batteries run flat more often than I'd like. The 1n is fine, but the 2n is battery-hungry (not quantified), the 2-SP draws 1 mA of current (down to 13 uA when in one of the red modes), and the new-circuit OM-4, which until recently drew just 6–8 uA in any mode, now draws some 300–800 uA in all modes for some as-yet-unknown reason.

The whys of those draws are topics for another day, but I'd like to develop a simple on/off switch that can be added to any camera that becomes problematic.

I'm a user and not a collector, so I won't hesitate to bring out the drill if need be, but I'm unfortunately an electronics dunce, so how to implement such a switch isn't as trivial to me as it will be to many. I'd like it to be as unobtrusive as possible and not be easily activated when the camera is knocking around in a bag. That and for it to be applicable to any of the OM bodies and be minimally invasive should I want to return the stock state.

So far, I've thought of drilling a small hole in the middle of the coin slot in the battery cover, tapping a thread in it, and having a low-profile plastic knurled screw (something like the one that adjusts the diopter on the OM-4) that one tightens to insert and thus depress the batteries against the spring and break the contact with the cover, serving as an off switch. This might not work if the cover is too thin for a tapped thread to hold the screw, which seems likely.

Does anyone know of a low-profile type of mechanical switch that might perform the same function or have any bright ideas about a simple electronic version?

 

[Marcelo Paniagua]

I just follow manufacturers recommendations and remove the batteries when not in use

I have plenty of OM bodies so often forgot which ones have batteries so often remove them after using them, except 1n, which is the one that I grab the most. Battery keeps forever so not really worried/concerned.

 

[koraks]

minimally invasive should I want to return the stock state

That'll be very challenging.

One option that comes to mind is to replace the standard battery holder with a custom-made variant that has a switch mounted onto it. But it'll protrude from the camera, making it easy to inadvertently move, and it'll be annoying since the camera won't sit level on a tabletop etc. anymore. Similar arguments will apply to virtually every other approach.

I just follow manufacturers recommendations and remove the batteries when not in use

Best option IMO.

Also a good option: figure out why the battery draw has increased so much and solve the cause. Leaky capacitors come to mind, of course.

 

[Marcelo Paniagua]

Also a good option: figure out why the battery draw has increased so much and solve the cause. Leaky capacitors come to mind, of course.

That sounds plausible. I did a bit of electronics on the 90s and a faulty capacitor may be a cause. Also not a good thing since many of the capacitor on this cameras are too tiny to be easily replaced.

 

[koraks]

That sounds plausible.

Yes, and this is especially the case in 1980s cameras. In the 1980s, tantalum capacitors began to be more commonly used, as they have the advantage of a high volumetric capacitance. An attractive property in cameras! The drawback is that minor impurities in manufacturing result in leakage of these capacitors. This leakage is extremely small at the start, but tends to be self-reinforcing, meaning it can "suddenly" spiral out of control. Which sounds familiar reading back the OP:

the new-circuit OM-4, which until recently drew just 6–8 uA in any mode, now draws some 300–800 uA in all modes for some as-yet-unknown reason

 

[reddesert]

My idea is not as easy to operate as a switch, but installing a switch in such close quarters isn't easy. Remove the battery cover and cut a piece of blue painter's tape to fit the inside surface of the cover, insulating the cover and breaking the circuit. When you want to use the camera, open the cover and take off the tape, sticking it on the bottom plate of the camera for safekeeping. At the end of the day, stick the tape back into the cover. (Obviously, this was inspired by devices that ship with batteries installed where you have to remove a little insulating piece of clear plastic before using.) The only real advantage over removing the batteries is that you don't grab the camera, go out, and then remember the batteries are at home.

Carrying the camera around with batteries on for several hours during the day shouldn't drain them that much. It's the storage over days or months that will drain them.

 

[jonty]

Thanks for the replies you three. I can see I asked the right people.

It's true that removing the batteries is a solution of a sort, although it takes longer than a switch, the coin slot accumulates wear over time, and the batteries need to be stored somewhere. I just thought I might be able to engineer something small and simple that avoids these drawbacks. I shoot in a frequent but sparse manner (pretty much every day, but perhaps just a few shots a day), which makes removing batteries more of a pain than for occasional but intense shooters.

Koraks, you're quite right than any solution would protrude from the bottom slightly, although my cameras are almost always stored in my bag, so I'd never notice that it would no longer sit flat. By 'minimally invasive' I meant that any permanent 'damage' to the camera would be minimal and constitute as little scarring as possible once the mod is undone. A small hole in the middle of the coin slot would be minimal enough, for example.

I'm sure I'm showing my ignorance here, but if I was to find a low-profile threaded 14mm switch with the same thread spacing and pitch that would take the place of the battery cap and had it so that one of the two of the pins contact the top battery and the other is wired to the body, would this work to open and close the circuit? Something like the following:

Of course, repair is the real solution. The camera is at the technician now, and his initial speculation was exactly as you suggest, koraks: that the capacitors have sprung leaks. Fingers crossed that they can be replaced.

 

[jonty]

I was amused to see the following mod on an OM-4 I found for sale.

The thumbscrew relieves pressure on the batteries to break the circuit and stop drain. I like it! Although I would think it could be made significantly more compact.

 

[Chuck1]

Not 100% sure, but does the motor drive/ winder power the camera and allow it to run without batteries? it's quick and easy to pull out the battery tray/pack. There pretty small and provide a nice grip.