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Johnboothe
Tinkerer
Username: Johnboothe
Post Number: 1
Registered: 04-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 08, 2010 - 12:29 pm: | 
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My Olympus XA was drenched in sea water about five years ago and stopped working completely (not surprisingly). I recently decided to have a go at getting it working again and after taking apart the shutter button assembly and cleaning it, the shutter is firing again and the light meter is responding to light. However, comparing it to my (reliable) gossen meter, and to other cameras, the XA meter is reading around 2 and a half stops under. The shutter, going off the sound at slower speeds, is pretty close to the XA's reading. The camera is thus overexposing by around two and a half stops. As far as I can tell, this seems pretty consistent across a range of brightnesses.
Does anyone have any suggestions for the likely cause of this? As I understand it, the meter needle and the shutter controller work off two different circuits, so it's possible for one to be accurate while the other is inaccurate. However, since my shutter and needle seem to be agreeing, it would seem unlikely that the problem is with a component which only affects one system. It seems likely that the troublesome component is one which affects both the needle and the shutter. Could this be the photo cell itself?
Everything else I have been able to visibly test in the camera seems ok - the aperture control is working and controlling exposure appropriately; the film speed dial affects exposure appropriately etc, though I haven't dismantled the front assembly yet, where I believe the photo cell is housed as I wasn't sure I'd be able to get it back together.
Does anyone with any knowledge of the internals of this camera have any suggestions as to what the problem might be (and how to fix it)? Many thanks in advance. |
Mareklew
Tinkerer
Username: Mareklew
Post Number: 42
Registered: 03-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 08, 2010 - 12:54 pm: |
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It could be salt in your camera. Don't power anything drenched in salt water before completely disassembling it and thoroughly cleaning with fresh water (this applies to any device, not only a camera). There's going to be some salt residue inside, and with moisture drawn from the air it will form conductive and aggressive mud. Adding electricity into the equation, even a button battery, will lead to electrochemical corrosion, even if the circuit might seem to work initially.
This seems to be likely reason for your trouble now. CdS cells drop their resistance as light levels increase. If some of the current flows through salt, it will seem to the circuitry, that the light level is higher, than it actually is.
Don't try to just compensate for it, if you don't remove the salt risk, it will kill your camera - exactly how long it will take, depends on where the salt residue is, how much metal is left there and how much current passes, but it may take anywhere between minutes and days (related to power-on time, not necessarily shelf time).
Marek
PS: for ANY device, that contains a battery: Shall it ever drop in water, REMOVE all batteries IMMEDIATELY. If it was dunked in fresh water (a rain puddle, a public fountain, a lake), chances are, that drying alone will cure it. But drying isn't going to take half an hour in the trunk of your car - it may take up to a week in a dry, warm place. I have a Nokia mobile phone, that was scavenged from a city fountain drain, sitting there for several days already, albeit with no battery. Thorough cleaning with fresh water and a week of drying brought it back, it still works two years later. |
Johnboothe
Tinkerer
Username: Johnboothe
Post Number: 2
Registered: 04-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 08, 2010 - 06:01 pm: |
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Thanks for your advice, Marek. So just to be clear then, you recommend cleaning all the electrical components with water (obviously without the batteries in). Are you sure this won't harm anything - including the CdS cells? Won't water cause corrosion? |
David_nebenzahl
Tinkerer
Username: David_nebenzahl
Post Number: 265
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 08, 2010 - 07:52 pm: |
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Plain water won't cause corrosion. That's why a camera dunked in salt water wants to be rinsed out. The idea is to flush everything with plain water, get as much water out as possible and then let it dry a good long time before powering it up again. |
Mareklew
Tinkerer
Username: Mareklew
Post Number: 44
Registered: 03-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 09, 2010 - 01:02 am: |
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Use distilled water. You can buy it cheaply in stores holding household cleaning stuff - it's sold for steam-ironing clothes, for topping car battery electrolyte etc. Costs about $1 per gallon where I live.
Don't get me wrong: even clean water CAN do damage to camera interior. But you have already had salt water there, which is much worse, so the damage is done. You can't use alcohol etc., because some of the waste saltwater deposited there is easily soluble only in water. So clean it all with water FIRST, then do the usual CLA after all saltwater deposits are gone and camera components several times flushed with fresh water.
Note, that water will take very long to evaporate from hard-to-reach places, so best is to disassemble the device in question as far, as only possible prior to washing.
Leave washed components in a warm, dry place for a week afterward, first then do final assembly.
You might need to adjust meter afterward, but it's unlikely CdS cell would be affected by water (it is sealed, else it would get wasted by air contact). Be careful about the galvanometer though! It won't get damaged by water contact, but it's mechanically very fragile.
Marek |
Johnboothe
Tinkerer
Username: Johnboothe
Post Number: 3
Registered: 04-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 10, 2010 - 04:05 pm: |
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Thanks guys. This is really useful. I'll follow your advice when I get some time.
If I do all this and the metering is still out, does anyone know how to make this adjustment? Is there an adjustment for the shutter also? |
Mareklew
Tinkerer
Username: Mareklew
Post Number: 48
Registered: 03-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 10, 2010 - 05:26 pm: |
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Have a look in the "Repair manuals" section, I think there was RepMan for XA. Not sure if it has a description of adjustment proc though.
Marek |
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