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Eurekaiv
Tinkerer
Username: Eurekaiv
Post Number: 1
Registered: 11-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 29, 2011 - 03:48 pm: | 
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I know this camera probably isn't worth enough to fix but I wouldn't be me if I didn't at least give it a shot. I've read through tons of posts and found a couple mentions of my problem but no real process or solution and unfortunately the repair guide online is for the XA which appears to be a bit different.
So here goes... the trouble I'm having is:
The camera turns on, battery test works and self timer fires but the shutter speed does nothing but shoot at approximately 2 seconds and the slow shutter speed indicator light stays on regardless of changing lighting conditions or ISO selection. If I pop the flash mounting switch out of the way and enable the flash it will fire at the flash sync speed. I tried cleaning what appeared to be the magnet contact switches for the shutter and that changed nothing. The shutter will not fire in battery check mode and behaves the same as described above with the door open. The camera is in fairly nice shape otherwise and doesn't appear to have been dropped or damaged in any way. The internals looked clean and clear when I had it disassembled. Thanks in advance for any guidance on this.  |
Shutterbug2
Tinkerer
Username: Shutterbug2
Post Number: 73
Registered: 10-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 29, 2011 - 07:18 pm: |
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if memory serves me. there must be film loaded in camera. without film it,s taking light reading straight off film plain. throwing off shutter speed i think i read that in past post on xa,s. i,ve aquired 5 or 6 over years there nice pocket camera,s. some day i,ll have to run some film thru them. i keep at least one roll of exposed film around just to test the mechanics of cameras i collect. James |
Eurekaiv
Tinkerer
Username: Eurekaiv
Post Number: 2
Registered: 11-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 29, 2011 - 07:29 pm: |
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Hmm... okay, I'll give it a shot. At worst I burn a couple frames on a roll and wind it back to the leader if it still doesn't work.
Edit: Didn't make any difference. The meter on this guy is a CDS cell above the lens so I don't think having film loaded or not should effect it's functionality. |
Mareklew
Tinkerer
Username: Mareklew
Post Number: 261
Registered: 03-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 30, 2011 - 05:10 am: |
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The XA series has really simple AE system: Shutter opens, then a capacitor gets charged through the CdS cell till it reaches a threshold charge and the shutter closes. The brighter the light, the more current can flow through the CdS and so the shorter it takes to charge the said capacitor up = shorter shutter time.
There's a separate circuit that closes the shutter after certain time no matter what, just to avoid battery drain if you fired the camera inside your pocket. This time delay is more or less variable from unit to unit.
If your camera is exposing always long, there's a possibility, that the first circuit (the actual auto-exposure) doesn't work at all and it's the safety circuit that closes the shutter.
Anyway, this sounds like either:
A) the CdS cell had too high a resistance, possibly even infinite one (= a connetion break). One possibility is aged cell, but more likely it's dirt, broken wire or even dislocated cell (=it doesn't sit behind it's window where it should).
B) the timing capacitor is leaky. I don't know if it's an electrolytic cap, but if it is, then it may be leaking charge because of it's age. It will either reach threshold too late, or never.
C) The IC is bad. This is always a risk, but don't overestimate it.
Issues A&B are easy to find and to tackle if you can take the camera apart and have a multimeter handy...
Marek |
Eurekaiv
Tinkerer
Username: Eurekaiv
Post Number: 3
Registered: 11-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 30, 2011 - 10:58 am: |
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Hi Marek,
I have a multimeter handy and I'm handy with a multimeter. I've also already had the camera apart (and of course lost the dowel that snaps the door open —and subsequently repaired it with a clipping from the straw on my can of compressed air) so taking it apart further should be no trouble.
The CdS cell looks to be in the proper position and has no noticeable dirt on or near it so I'm going to guess a dead cell or broken wire. I think dead cell is most likely. I'd be surprised if this camera had an electrolytic inside as there's very little room. I'd suspect a tantalum cap based on size and age and I think I saw one in the top of the camera when I had it apart previously. In any case, will the XA manual show me how to get to these parts to check them? It appeared different enough (with a different metering scheme since its manual) that I felt uncomfortable following along with it. |
Eurekaiv
Tinkerer
Username: Eurekaiv
Post Number: 4
Registered: 11-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 30, 2011 - 09:55 pm: |
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I took it partially back apart. The CdS seems to be responding to light changes when measured with my meter. When I cover it, it reads approx 2.5Mohm and with my magnifying lamp right in front of it I get around 3.5Mohm. I'm not sure which cap is the timing cap but the one that appears connected to the CdS cell on the PCB across the top of the camera is a .33uf tantalum that measures within tolerance. The PCB appears fine and no connections seem compromised. |
