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Waynemel
Tinkerer
Username: Waynemel
Post Number: 81
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 30, 2010 - 09:26 pm: | 
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The meter on this camera is not functioning. I don't think it is a power issue, since all wires and contacts are clean. What I have noticed is that the meter needle does not spring back to its normal position when moved manually. I can see the light coil spring that is part of the meter assembly, and it appears that the needle is connected properly. It seems as though the spring is not strong enough to move the needle back to its resting position. What might be causing the needle to stick? |
Neuberger
Tinkerer
Username: Neuberger
Post Number: 4
Registered: 01-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 01, 2010 - 02:56 am: |
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An ohmmeter helps you to find out if the wiring is ok. Your problem seems a mechanical one and there are often screws and other tiny metal chips that are attracted and then caught by the magnetic parts of the moving-coil meter, so that a proper rotation of the coil is no longer possible.
Another problem with those meters is that the bearings can become too tight over time for a reason I do not know. I think, however, that either the frame of the coil or the material to which the bearing pins are glued somehow expands resulting in too much tension or friction in the fulcrum shafts. Loosening the setscrews of the bearings may cure this. |
Waynemel
Tinkerer
Username: Waynemel
Post Number: 82
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:41 pm: |
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Thanks for the tips. I did adjust the setscrews, and the needle did begin to move freely. At first the needle was responding to light, but now it doesn't move. I have voltage at the two pots on the top of the meter. I did notice a few "loose ends" of copper wire on the coil. This doesn't seem right does it? If these are broken wires, would that render the meter inoperative? Is there any way to fix this, or at least check if the coil is good? |
Neuberger
Tinkerer
Username: Neuberger
Post Number: 5
Registered: 01-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 08:01 am: |
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These coils are made from awfully thin lacquered wire which is then stripped bare at the end and soldered to the two soldering points for the wires (red or white, batt. neg. and black, common ground, usually batt. pos.). Often the very end of the thin wire is still visible at the soldering joint so that one could think it has come loose, whether the coil is ok can easily be measured with an ohmmeter. Soldering this thin wire is only possible with a low-wattage soldering needle (and a magnifying glass), but the whole business is very problematic, it is often easier to find a good meter from a junker or parts camera. If one can see several "loose ends" as you write protruding from the coil it is very probably shot. |
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