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Message |
    
wiggy
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, July 04, 2005 - 10:05 pm: | 
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Hello I am new here and to camera repair so please be gentile 
I have come in to possession of a Nikon FM (I think) that was rebuilt from two broken cameras a few years back. It all works fine but the light meter is not calibrated. If any one could give me some advice on how to go about calibrating the light meter it would be greatly appreciated. |
P Laskey
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, July 05, 2005 - 05:55 am: |
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Personally I would only entrust this job to a technician. There are quite a lot of electronics in there compared to earlier manual exposure cameras. Barring that FMs and FEs are plentiful on Ebay!
PL |
wiggy
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, July 05, 2005 - 08:14 am: |
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The electronics will not be a problem for me as I am very into electronics (bit of a technophile ) plus I do have two other broken FMs to “play with”. I think the calibration is done by way of the three dials (variable resistors?) on the icb to the left of the prism. But other then that I have no clue. If some one has a circuit diagram or exploded diagram of a push in the right direction it would be very helpful. |
P Laskey
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, July 05, 2005 - 12:58 pm: |
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This is what I've been able to find out so far. There are two main types of circuit board for the FM, the old type and the new one. The potentiometer adjusters are in different places. On the old type, the one at 6 o' clock (looking from the rear of the camera) is offset voltage - do not touch this. The one at seven o clock adjusts the meter at low light values, and the one at 10 o' clock adjacent to the strap lug adjusts high light level sensitivity. On the new type (more common) offset voltage is 10 o' clock, high value adjustment 5 o' clock and low value 7 o' clock. It's best to fix the camera pointing at a constant light source and take a reference reading using another camera or hand held meter, then try to adjust the FM meter so it gives the same readings at all combinations of shutter speed and aperture. Usually it helps to cover the pentaprism with black paper to stop stray light distorting the reading.
PL |
wiggy
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 07, 2005 - 05:21 am: |
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Thank you very much. This is just what I needed, judging from the pot position I have the older icb. I calibrated the meter using a gray card in direct sun light against a Minolta Dynax 505si and a 308b. The meter is now giving consistent results in all lighting conditions.
Cheers. |
P Laskey
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 07, 2005 - 08:55 am: |
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Glad my advice worked for once, although I looked it up in Nikon Camera Repair Manual by Thomas Tomosy, an essential book for all Nikonophiles.
PL |
