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Nizo 801 lightmeter dead - what do?


Alessandro Malfatti
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So the lightmeter system on my Nizo 801 died on me. I say lightmeter system, as apparently the metering is linked to the iris. This means I can't set aperture manually either. Can this be fixed at all?

I could live with a non-working light meter but manually adjustable iris, if that were a solution.

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  • 1 month later...

Are you sure your light meter batteries aren't dead? Those weincell 1.35v batteries kinda suck and easily lose charge over time if not stored with the sticker on it. With those batteries dead, even manual metering won't work in that camera, one of the only major design flaws of an otherwise incredible camera.

I suggest buying new batteries and seeing if that brings it all back to life.

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Just to double check here, did you test the meter batteries via the Meter Battery Test Button in the middle of the Auto/Manual control knob?  Turn on camera power, test to see if the needle deflects to about middle scale.  If so, then the power from the meter batteries is reaching the metering aperture drive system.  If not, then there isn't any power getting to it, thus you won't have Auto or Manual control.  This could be due to an electrical short from mild corrosion either in the battery compartment, or if it existed before and was cleaned....the corrosion could be just inside beyond the battery chamber on one of the wires.  If not there, then it could be where the wires run to the circuit board, if not there, then where the wires run the Galvonometer and Control Knob regions.  This can be involved work to find the problem and is best left to someone that knows how to do this type of work.  However, check whatever you're able to check.  Usually the metering system just doesn't die. Even if the photo sensor which reads the light incoming fails, that only runs the Auto system, the Manual control system should still work since it's just a rheostat type design to move the aperture needle.  Also, it could be possible that the needle is jammed.......you'd have to remove the right side silver body shell cover carefully, and then with a toothpick or thin coffee stirrer or something similar, ever so gently touch and see if the needle can be moved physically.  Very gentle here....if so, then power it up again and see if it can be moved via the Control Knob....if not....and it's not jammed now, then there is definitely a power short somewhere in the power supply system, anywhere from the battery chamber, the wires leading to the circuit board etc as I mentioned earlier.  Good luck, I'm hoping maybe you get lucky and it comes back to life for you.

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  • 2 weeks later...
  • 2 weeks later...

If the meter unit is getting power and reacts to the Battery Check Button being pressed in, then the needle should deflect to the F/8 position on the aperture scale indicating the batteries are good.  If it does that but won't move past F/2.8 when in Manual Mode, then it could be due to light tarnish on the adjustment metallics since it's essentially a potentiameter like a volume control to adjust the current flow of power to the aperture needle.   This would require removing the control side panel cover of the camera and cleaning the Manual Potentiometer gently with a cotton swap tip moistened with electric contact cleaner for electronics.  If this doesn't work, the issue is more involved.  IF the needle doesn't move past F/2.8 when in Battery Check mode, then I suspect the needle is getting stuck and won't go further for some reason, or, there just isn't enough power.  Assuming the batteries are good, the problem is insufficient current flow to the potentiometer, and that would require checking the wiring path with a fine circuit meter to check and see where the power loss is in the wiring harness/circuit board.  It could just be losing power as it flows through the Auto/Manual Control, so once that is cleaned, it might improve.  If just wiping the metallic ring that the control uses to adjust current flow doesn't work, you can try spraying the entire unit with the cleaner.  Make sure you are using a fine electronic circuit spray cleaner intended for delicate electronics!  There are some for electrical circuits that are stronger since they aren't made for delicate electronics.  Be careful to avoid any serious over spray into the camera, and allow several minutes or more for the solution to evaporate prior to testing it again.

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