davidsimon

Update: blue and orange wires to the CDS were soldered to the incorrect contacts (according to the wiring schematic) I've swapped these over but no change to the meter behaviour, which is not too surprising as the CDS is basically just a variable resistor right? Perhaps the CDS is malfunctioning, I do get a change in resistance through it when varying the light input, but only a very small change. What should the resistance range be on these things?

Not sure if this is the right place to post this, but I could use some advice on repairing the meter on my Auto S3. I've fully stripped the camera and isolated the meter circuit (photos attached), there are clear signs of previous repairs, I beleive someone has added in a new variable resistor as shown in the attached. My confusion is in determining the correct values of these resistors to make the circuit function correctly, the S3 repair manual doesn't go into this level of detail. When the battery is installed, the meter immediately jumps to F16 (no light on the CDS). Adjusting the variable resistor to its minimum resistance and shining light on the CDS caused the meter to move back down to around f8, but no further. This seems backwards, more light should move the needle up not down? I've checked the circuit against the S3 repair manual and all seems correct. I've checked all wires and all are reading zero resistance (so seemingly no corrosion). The battery contacts are in good condition and polarity is correct. All soldering is good at the CDS contacts in the lens. Can anyone recommend a sequence of testing that would identify the issue?

I've checked what you describe, and yes when looking through the viewfinder, changing the aperture on the lens does affect the light meter and does change the shutter speed. So for example, at f1.8 the meter indicates a shutter speed of 1/125 but actually fires at around 1/15th. Then when the aperture is changed to f8, the meter indicates 1/30th but the shutter fires at around 1 second!

That's my understanding too, and the problem is that I did have a film in the camera at the time of testing!

I'm having some issues with metering in auto mode on an OM-2. The problem is the actual shutter speed during exposure is much longer than the shutter speed indicated by the meter. For example the indicated speed might be 1/125 but the actual shutter fires at around 1/15th or slower (judging by ear). Here's what I know so far: -Viewfinder metering is consistent between auto and manual modes. -Viewfinder metering is consistent with my DSLR at the same ISO/Aperture, therefore the issue must lie with the actual shutter speed being selected by the camera. -My testing was done with brand new silver oxide cells fitted and film loaded. -In manual mode, shutter speeds sound about right (by my not-so calibrated ears) -I replaced the mirror stop foam as it was a bit sticky. My initial conclusion is that there is a problem with the two SBC blue light sensors in the bottom of the mirror-box, which I guess must be reading incorrectly and causing the slow shutter speeds? I checked if they were dirty, one had a little dust but gently cleaning it made no difference. I did also notice that the Manual/Off/Auto switch on top of the camera is a bit tempremental, and sometimes requires a wiggle to make contact at the chosen setting. Could this be the cause of the auto-mode issue (doesn't seem likely though)? So my question is, what is the next step in my investigation? I understand there is variable resistor under the mirror box which controls the SBC metering circuit, would it simply be a case of adjusting this to correct the speeds, and is this easily accessible under the mirror box base? Otherwise, are there any other common faults here that I can check for? For info, I'm fairly competent at basic camera repairs and have tackled some pretty challenging jobs on other cameras. I say this because I'm keen to try and get this repaired myself, however I will submit to a professional repair if it's out of my reach. Any advice is greatly appreciated.

Hi All, I'm trying to repair an AE-1 (non-program) with a faulty meter. Upon half-pressing the shutter release the meter bottoms out every time, regardless of camera settings or the amount of available light. After trawling the forums it seems the issue may be with the PX1 IC light sensor behind the prism, perhaps through bad solder connections? I've removed the top cover to inspect, and from what I can see the surface of the sensor looks dirty or possibly corroded (photo attached). And indeed when I shine a bright light directly on to the sensor, I do get some movement in the meter needle through the viewfinder. So I've concluded that the sensor is indeed working, but just not very well, probably due to the surface dirt/corrosion. So my question is, what next? It doesn't look straightforward to replace the sensor, so can I instead compensate for the poor sensitivity via the series of galvanometers above the prism? How would i go about this? Or is there a technique to revive the sensor? I guess it would help if someone could point me in the direction of a service manual for the camera, despite a lengthy search I've been unable to track one down. And finally, this isn't a valuable camera and I'm not looking to buy another. I'm just too stubborn to let it die without a fight. Thanks

I just bought a rather splendid OM-1n off the 'bay and it came with this rather nifty replacement battery compartment pre-installed, which is perfectly sized for a pair of SR44W's, and also swaps the battery terminal to the opposite side for easy installation of the required voltage dropping diode. Does anyone recognise this new compartment and advise where I can get more of them? Perhaps it's been cannibalized from a different camera, I'm not sure. Its the neatest upgrade I've seen so far on one of these lovely cameras.